November 2013, Volume 55 Issue 11, Pages 998每1180.

Cover Caption: PUP and Cytokinin Transport
About the cover: One PUP-type transporter, OsPUP7, plays an important role in cytokinin transport in rice, thus regulates both developmental and stress responses (Qi and Xiong, pp. 1119每1135). The picture on the cover shows expressions of the OsPUP7 in vascular bundles of culm using transgenic rice carrying an OsPUP7::GUS fusion construct.


Prepare for Future Challenges  
Author: Chun-Ming Liu
Journal of Integrative Plant Biology 2013 55(11): 999每1001
Published Online: November 5, 2013
DOI: 10.1111/jipb.12120
Abstract (Browse 712)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Cell and Developmental Biology
AtFH16, an Arabidopsis Type II Formin, Binds and Bundles both Microfilaments and Microtubules, and Preferentially Binds to Microtubules
Author: Jiaojiao Wang, Yi Zhang, Jing Wu, Lei Meng and Haiyun Ren
Journal of Integrative Plant Biology 2013 55(11): 1002每1015
Published Online: October 23, 2013
DOI: 10.1111/jipb.12089

Formins are well-known regulators that participate in the organization of the actin cytoskeleton in organisms. The Arabidopsis thaliana L. genome encodes 21 formins, which can be divided into two distinct subfamilies. However, type II formins have to date been less well characterized. Here, we cloned a type II formin, AtFH16, and characterized its biochemical activities on actin and microtubule dynamics. The results show that the FH1FH2 structure of AtFH16 cannot nucleate actin polymerization efficiently, but can bind and bundle microfilaments. AtFH16 FH1FH2 is also able to bind and bundle microtubules, and preferentially binds microtubules over microfilaments in vitro. In addition, AtFH16 FH1FH2 co-localizes with microtubules in onion epidermal cells, indicating a higher binding affinity of AtFH16 FH1FH2 for microtubules rather than microfilaments in vivo. In conclusion, AtFH16 is able to interact with both microfilaments and microtubules, suggesting that AtFH16 probably functions as a bifunctional protein, and may thus participate in plant cellular processes.

Wang J, Zhang Y, Wu J, Meng L, Ren H (2013) AtFH16, an Arabidopsis type II formin, binds and bundles both microfilaments and microtubules, and preferentially binds to microtubules. J. Integr. Plant Biol. 55(11), 1002–1015.

Abstract (Browse 1187)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Characterization and Fine Mapping of a Novel Rice Narrow Leaf Mutant nal9
Author: Wei Li, Chao Wu, Guocheng Hu, Li Xing, Wenjing Qian, Huamin Si, Zongxiu Sun, Xingchun Wang, Yaping Fu and Wenzhen Liu
Journal of Integrative Plant Biology 2013 55(11): 1016每1025
Published Online: September 10, 2013
DOI: 10.1111/jipb.12098

A narrow leaf mutant was isolated from transgenic rice (Oryza sativa L.) lines carrying a T-DNA insertion. The mutant is characterized by narrow leaves during its whole growth period, and was named nal9 (narrow leaf 9). The mutant also has other phenotypes, such as light green leaves at the seedling stage, reduced plant height, a small panicle and increased tillering. Genetic analysis revealed that the mutation is controlled by a single recessive gene. A hygromycin resistance assay showed that the mutation was not caused by T-DNA insertion, so a map-based cloning strategy was employed to isolate the nal9 gene. The mutant individuals from the F2 generations of a cross between the nal9 mutant and Longtepu were used for mapping. With 24 F2 mutants, the nal9 gene was preliminarily mapped near the marker RM156 on the chromosome 3. New INDEL markers were then designed based on the sequence differences between japonica and indica at the region near RM156. The nal9 gene was finally located in a 69.3 kb region between the markers V239B and V239G within BAC OJ1212_C05 by chromosome walking. Sequence and expression analysis showed that an ATP-dependent Clp protease proteolytic subunit gene (ClpP) was most likely to be the nal9 gene. Furthermore, the nal9 mutation was rescued by transformation of the ClpP cDNA driven by the 35S promoter. Accordingly, the ClpP gene was identified as the NAL9 gene. Our results provide a basis for functional studies of NAL9 in future work.

Li W, Wu C, Hu G, Xing L, Qian W, Si H, Sun Z, Wang X, Fu Y, Liu W (2013) Characterization and fine mapping of a novel rice narrow leaf mutant nal9. J. Integr. Plant Biol. 55(11), 1016–1025.

Abstract (Browse 1627)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Novel Natural Allelic Variations at the Rht-1 Loci in Wheat
Author: Aixia Li, Wenlong Yang, Xueyuan Lou, Dongcheng Liu, Jiazhu Sun, Xiaoli Guo, Jing Wang, Yiwen Li, Kehui Zhan, Hong-Qing Ling and Aimin Zhang
Journal of Integrative Plant Biology 2013 55(11): 1026每1037
Published Online: November 5, 2013
DOI: 10.1111/jipb.12103

Plant height is an important agronomic trait. Dramatic increase in wheat yield during the “green revolution” is mainly due to the widespread utilization of the Reduced height (Rht)-1 gene. We analyzed the natural allelic variations of three homoeologous loci Rht-A1, Rht-B1, and Rht-D1 in Chinese wheat (Triticum aestivum L.) micro-core collections and the Rht-B1/D1 genotypes in over 1,500 bred cultivars and germplasms using a modified EcoTILLING. We identified six new Rht-A1 allelic variations (Rht-A1b–g), eight new Rht-B1 allelic variations (Rht-B1h–o), and six new Rht-D1 allelic variations (Rht-D1e–j). These allelic variations contain single nucleotide polymorphisms (SNPs) or small insertions and deletions in the coding or uncoding regions, involving two frame-shift mutations and 15 missenses. Of which, Rht-D1e and Rht-D1h resulted in the loss of interactions of GID1-DELLA-GID2, Rht-B1i could increase plant height. We found that the Rht-B1h contains the same SNPs and 197 bp fragment insertion as reported in Rht-B1c. Further detection of Rht-B1h in Tibet wheat germplasms and wheat relatives indicated that Rht-B1c may originate from Rht-B1h. These results suggest rich genetic diversity at the Rht-1 loci and provide new resources for wheat breeding.

Li A, Yang W, Lou X, Liu D, Sun J, Guo X, Wang J, Li Y, Zhan K, Ling HQ, Zhang A (2013) Novel natural allelic variations at the Rht坼1 loci in wheat. J. Integr. Plant Biol. 55(11), 1026–1037.

Abstract (Browse 1127)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Metabolism and Biochemistry
Integration of Metabolomics and Subcellular Organelle Expression Microarray to Increase Understanding the Organic Acid Changes in Post-harvest Citrus Fruit  
Author: Xiaohua Sun, Andan Zhu, Shuzhen Liu, Ling Sheng, Qiaoli Ma, Li Zhang, Elsayed Mohamed Elsayed Nishawy, Yunliu Zeng, Juan Xu, Zhaocheng Ma, Yunjiang Cheng and Xiuxin Deng
Journal of Integrative Plant Biology 2013 55(11): 1038每1053
Published Online: November 5, 2013
DOI: 10.1111/jipb.12083

Citric acid plays an important role in fresh fruit flavor and its adaptability to post-harvest storage conditions. In order to explore organic acid regulatory mechanisms in post-harvest citrus fruit, systematic biological analyses were conducted on stored Hirado Buntan Pummelo (HBP; Citrus grandis) fruits. High-performance capillary electrophoresis, subcellular organelle expression microarray, real-time quantitative reverse transcription polymerase chain reaction, gas chromatography mass spectrometry (GC-MS), and conventional physiological and biochemical analyses were undertaken. The results showed that the concentration of organic acids in HBP underwent a regular fluctuation. GC-MS-based metabolic profiling indicated that succinic acid, γ-aminobutyric acid (GABA), and glutamine contents increased, but 2-oxoglutaric acid content declined, which further confirmed that the GABA shunt may have some regulatory roles in organic acid catabolism processes. In addition, the concentration of organic acids was significantly correlated with senescence-related physiological processes, such as hydrogen peroxide content as well as superoxide dismutase and peroxidase activities, which showed that organic acids could be regarded as important parameters for measuring citrus fruit post-harvest senescence processes.

Sun X, Zhu A, Liu S, Sheng L, Ma Q, Zhang L, Nishawy EMS, Zeng Y, Xu J, Ma Z, Cheng Y, Deng X (2013) Integration of metabolomics and subcellular organelle expression microarray increases understanding of the organic acid changes in post坼harvest citrus fruit. J. Integr. Plant Biol. 55(11), 1038–1053.

Abstract (Browse 1557)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Molecular Physiology
Different B-Type Methionine Sulfoxide Reductases in Chlamydomonas May Protect the Alga against High-Light, Sulfur-Depletion, or Oxidative Stress
Author: Lei Zhao, Mei Chen, Dongmei Cheng, Haomeng Yang, Yongle Sun, Heyi Zhou and Fang Huang
Journal of Integrative Plant Biology 2013 55(11): 1054每1068
Published Online: October 28, 2013
DOI: 10.1111/jipb.12104

The genome of unicellular green alga Chlamydomonas reinhardtii contains four genes encoding B-type methionine sulfoxide reductases, MSRB1.1, MSRB1.2, MSRB2.1, and MSRB2.2, with functions largely unknown. To understand the cell defense system mediated by the methionine sulfoxide reductases in Chlamydomonas, we analyzed expression and physiological roles of the MSRBs under different abiotic stress conditions using immunoblotting and quantitative polymerase chain reaction (PCR) analyses. We showed that the MSRB2.2 protein was accumulated in cells treated with high light (1,300 µE/m2 per s), whereas MSRB1.1 was accumulated in the cells under 1 mmol/L H2O2 treatment or sulfur depletion. We observed that the cells with the MSRB2.2 knockdown and overexpression displayed increased and decreased sensitivity to high light, respectively, based on in situ chlorophyll a fluorescence measures. We also observed that the cells with the MSRB1.1 knockdown and overexpression displayed decreased and increased tolerance to sulfur-depletion and oxidative stresses, respectively, based on growth and H2-producing performance. The physiological implications revealed from the experimental data highlight the importance of MSRB2.2 and MSRB1.1 in protecting Chlamydomonas cells against adverse conditions such as high-light, sulfur-depletion, and oxidative stresses.

Zhao L, Chen M, Cheng D, Yang H, Sun Y, Zhou H, Huang F (2013) Different B坼type methionine sulfoxide reductases in Chlamydomonas may protect the alga against high坼light, sulfur坼depletion, or oxidative stress. J. Integr. Plant Biol. 55(11), 1054–1068.

Abstract (Browse 1318)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Phylogeny and Classification of Prunus sensu lato (Rosaceae)
Author: Shuo Shi, Jinlu Li, Jiahui Sun, Jing Yu and Shiliang Zhou
Journal of Integrative Plant Biology 2013 55(11): 1069每1079
Published Online: October 28, 2013
DOI: 10.1111/jipb.12095

The classification of the economically important genus Prunus L. sensu lato (s.l.) is controversial due to the high levels of convergent or the parallel evolution of morphological characters. In the present study, phylogenetic analyses of fifteen main segregates of Prunus s.l. represented by eighty-four species were conducted with maximum parsimony and Bayesian approaches using twelve chloroplast regions (atpB-rbcL, matK, ndhF, psbA-trnH, rbcL, rpL16, rpoC1, rps16, trnS-G, trnL, trnL-F and ycf1) and three nuclear genes (ITS, s6pdh and SbeI) to explore their infrageneric relationships. The results of these analyses were used to develop a new, phylogeny-based classification of Prunus s.l. Our phylogenetic reconstructions resolved three main clades of Prunus s.l. with strong supports. We adopted a broad-sensed genus, Prunus, and recognised three subgenera corresponding to the three main clades: subgenus Padus, subgenus Cerasus and subgenus Prunus. Seven sections of subgenus Prunus were recognised. The dwarf cherries, which were previously assigned to subgenus Cerasus, were included in this subgenus Prunus. One new section name, Prunus L. subgenus Prunus section Persicae (T. T. Yü & L. T. Lu) S. L. Zhou and one new species name, Prunus tianshanica (Pojarkov) S. Shi, were proposed.

Shi S, Li J, Sun J, Yu J, Zhou S (2013) Phylogeny and classification of Prunus sensu lato (Rosaceae). J. Integr. Plant Biol. 55(11), 1069–1079.

Abstract (Browse 1150)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Deciphering Ascorbic Acid Regulatory Pathways in Ripening Tomato Fruit Using a Weighted Gene Correlation Network Analysis Approach
Author: Chao Gao, Zheng Ju, Shan Li, Jinhua Zuo, Daqi Fu, Huiqin Tian, Yunbo Luo and Benzhong Zhu
Journal of Integrative Plant Biology 2013 55(11): 1080每1091
Published Online: August 23, 2013
DOI: 10.1111/jipb.12079

Genotype is generally determined by the co-expression of diverse genes and multiple regulatory pathways in plants. Gene co-expression analysis combining with physiological trait data provides very important information about the gene function and regulatory mechanism. L-Ascorbic acid (AsA), which is an essential nutrient component for human health and plant metabolism, plays key roles in diverse biological processes such as cell cycle, cell expansion, stress resistance, hormone synthesis, and signaling. Here, we applied a weighted gene correlation network analysis approach based on gene expression values and AsA content data in ripening tomato (Solanum lycopersicum L.) fruit with different AsA content levels, which leads to identification of AsA relevant modules and vital genes in AsA regulatory pathways. Twenty-four modules were compartmentalized according to gene expression profiling. Among these modules, one negatively related module containing genes involved in redox processes and one positively related module enriched with genes involved in AsA biosynthetic and recycling pathways were further analyzed. The present work herein indicates that redox pathways as well as hormone-signal pathways are closely correlated with AsA accumulation in ripening tomato fruit, and allowed us to prioritize candidate genes for follow-up studies to dissect this interplay at the biochemical and molecular level.

Gao C, Ju Z, Li S, Zuo J, Fu D, Tian H, Luo Y, Zhu B (2013) Deciphering ascorbic acid regulatory pathways in ripening tomato fruit using a weighted gene correlation network analysis approach. J. Integr. Plant Biol. 55(11), 1080–1091.

Abstract (Browse 1053)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Site-Specific Gene Targeting Using Transcription Activator-Like Effector (TALE)-Based Nuclease in Brassica oleracea
Author: Zijian Sun, Nianzu Li, Guodong Huang, Junqiang Xu, Yu Pan, Zhimin Wang, Qinglin Tang, Ming Song and Xiaojia Wang
Journal of Integrative Plant Biology 2013 55(11): 1092每1103
Published Online: September 18, 2013
DOI: 10.1111/jipb.12091

Site-specific recognition modules with DNA nuclease have tremendous potential as molecular tools for genome targeting. The type III transcription activator-like effectors (TALEs) contain a DNA binding domain consisting of tandem repeats that can be engineered to bind user-defined specific DNA sequences. We demonstrated that customized TALE-based nucleases (TALENs), constructed using a method called “unit assembly”, specifically target the endogenous FRIGIDA gene in Brassica oleracea L. var. capitata L. The results indicate that the TALENs bound to the target site and cleaved double-strand DNA in vitro and in vivo, whereas the effector binding elements have a 23 bp spacer. The T7 endonuclease I assay and sequencing data show that TALENs made double-strand breaks, which were repaired by a non-homologous end-joining pathway within the target sequence. These data show the feasibility of applying customized TALENs to target and modify the genome with deletions in those organisms that are still in lacking gene target methods to provide germplasms in breeding improvement.

Sun Z, Li N, Huang G, Xu J, Pan Y, Wang Z, Tang Q, Song M, Wang X (2013) Site坼specific gene targeting using transcription activator坼like effector (TALE)坼based nuclease in Brassica oleracea. J. Integr. Plant Biol. 55(11), 1092–1103.

Abstract (Browse 1108)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
The tRNA 3∩-end Processing Enzyme tRNase Z2 Contributes to Chloroplast Biogenesis in Rice
Author: Tuan Long, Dong Guo, Dong He, Wenjie Shen and Xianghua Li
Journal of Integrative Plant Biology 2013 55(11): 1104-1118
Published Online: October 17, 2013
DOI: 10.1111/jipb.12102

tRNase Z (TRZ) is a ubiquitous endonuclease that removes the 3′-trailer from precursor tRNAs during maturation. In yeast and animals, TRZ regulates the cell cycle via its (t)RNA processing activity; however, its physiological function in higher plants has not been well characterized. This study describes the identification of a rice (Oryza sativa) TRZ2 mutant; plants homozygous for the osatrz2 mutation were albinos with deficient chlorophyll content. A microscopic analysis of the mutant plants revealed that the transition of proplastids to chloroplasts was arrested at an early stage, and the number and size of the plastids in callus cells was substantially decreased. A genetic complementation test and an RNA interference analysis confirmed that disruption of OsaTRZ2 was responsible for the mutant phenotype. OsaTRZ2 is expressed in all rice tissues, but is preferentially expressed in leaves, sheathes, and calli. OsaTRZ2 was subcellularly localized in chloroplasts, and displayed tRNA 3′-end processing activity in both in vitro and in vivo assays. In the osatrz2 mutants, transcription of plastid-encoded and nucleus-encoded RNA polymerases was severely reduced and moderately increased, respectively. These results suggest that the tRNA 3′ processing activity of OsaTRZ2 contributes to chloroplast biogenesis.

Long T, Guo D, He D, Shen W, Li X (2013) The tRNA 3′-end processing enzyme tRNase Z2 contributes to chloroplast biogenesis in rice. J. Integr. Plant Biol. 55(11), 1104–1118.

Abstract (Browse 1229)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Characterization of a Purine Permease Family Gene OsPUP7 Involved in Growth and Development Control in Rice  
Author: Zhuyun Qi and Lizhong Xiong
Journal of Integrative Plant Biology 2013 55(11): 1119每1135
Published Online: October 23, 2013
DOI: 10.1111/jipb.12101

In this study, PUP-type cytokinin transporter genes were identified in rice (Oryza sativa L.). The Oryza sativa purine permease (OsPUP) family has 12 members that show similar predicted protein sequences with AtPUPs. To reveal the functions of OsPUP genes, we searched the T-DNA mutant library of rice and found one mutant for the member OsPUP7. The T-DNA insertion caused a new transcript that encodes a protein with 26 amino acids different from the native OsPUP7 at the C-terminus. The mutant showed multiple phenotypic changes including increased plant height, big seeds, and delayed flowering. The mutant also showed increased sensitivity to drought and salt stresses and treatments with kinetin and abscisic acid. OsPUP7 is expressed mainly in the vascular bundle, pistil, and stamens. The measurement of cytokinins (CKs) showed that CK content in the mutant spikelets accumulated higher than that in the wild type. Moreover, uptake experiment in the yeast fcy2 mutant suggested that OsPUP7 has the ability to transport caffeine, a CK derivative. Our results indicate that the PUP transport system also exists in rice, and OsPUP7 has an important role in the transport of CK, thus affecting developmental process and stress responses.

Qi Z, Xiong L (2013) Characterization of a purine permease family gene OsPUP7 involved in growth and development control in rice. J. Integr. Plant Biol. 55(11), 1119–1135.

Abstract (Browse 1662)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Plant-environmental Interactions
Nitric Oxide and Brassinosteroids Mediated Fungal Endophyte-Induced Volatile Oil Production Through Protein Phosphorylation Pathways in Atractylodes lancea Plantlets
Author: Cheng-Gang Ren and Chuan-Chao Dai
Journal of Integrative Plant Biology 2013 55(11): 1136每1146
Published Online: September 10, 2013
DOI: 10.1111/jipb.12087
Fungal endophytes have been isolated from almost every plant, infecting their hosts without causing visible disease symptoms, and yet have still proved to be involved in plant secondary metabolites accumulation. To decipher the possible physiological mechanisms of the endophytic fungus–host interaction, the role of protein phosphorylation and the relationship between endophytic fungus-induced kinase activity and nitric oxide (NO) and brassinolide (BL) in endophyte-enhanced volatile oil accumulation in Atractylodes lancea plantlets were investigated using pharmacological and biochemical approaches. Inoculation with the endophytic fungus Gilmaniella sp. AL12 enhanced the activities of total protein phosphorylation, Ca2+-dependent protein kinase, and volatile oil accumulation in A. lancea plantlets. The upregulation of protein kinase activity could be blocked by the BL inhibitor brassinazole. Furthermore, pretreatments with the NO-specific scavenger cPTIO significantly reduced the increased activities of protein kinases in A. lancea plantlets inoculated with endophytic fungus. Pretreatments with different protein kinase inhibitors also reduced fungus-induced NO production and volatile oil accumulation, but had barely no effect on the BL level. These data suggest that protein phosphorylation is required for endophyte-induced volatile oil production in A. lancea plantlets, and that crosstalk between protein phosphorylation and the NO pathway may occur and act as a downstream signaling event of the BL pathway.

Ren C-G, Dai C-C (2013) Nitric oxide and brassinosteroids mediated fungal endophyte坼induced volatile oil production through protein phosphorylation pathways in Atractylodes lancea plantlets. J. Integr. Plant Biol. 55(11), 1136–1146.

Abstract (Browse 1076)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Early Transcriptomic Adaptation to Na2CO3 Stress Altered the Expression of a Quarter of the Total Genes in the Maize Genome and Exhibited Shared and Distinctive Profiles with NaCl and High pH Stresses
Author: Li-Min Zhang, Xiang-Guo Liu, Xin-Ning Qu, Ying Yu, Si-Ping Han, Yao Dou, Yao-Yao Xu, Hai-Chun Jing and Dong-Yun Hao
Journal of Integrative Plant Biology 2013 55(11): 1147每1165
Published Online: October 21, 2013
DOI: 10.1111/jipb.12100

Sodium carbonate (Na2CO3) presents a huge challenge to plants by the combined damaging effects of Na+, high pH, and CO32-. Little is known about the cellular responses to Na2CO3 stress. In this study, the transcriptome of maize (Zea mays L. cv. B73) roots exposed to Na2CO3 stress for 5 h was compared with those of NaCl and NaOH stresses. The expression of 8,319 genes, representing over a quarter of the total number of genes in the maize genome, was altered by Na2CO3 stress, and the downregulated genes (5,232) outnumbered the upregulated genes (3,087). The effects of Na2CO3 differed from those of NaCl and NaOH, primarily by downregulating different categories of genes. Pathways commonly altered by Na2CO3, NaCl, and NaOH were enriched in phenylpropanoid biosynthesis, oxidation of unsaturated fatty acids, ATP-binding cassette (ABC) transporters, as well as the metabolism of secondary metabolites. Genes for brassinosteroid biosynthesis were specifically upregulated by Na2CO3, while genes involved in ascorbate and aldarate metabolism, protein processing in the endoplasmic reticulum and by N-glycosylation, fatty acid biosynthesis, and the circadian rhythm were downregulated. This work provides the first holistic picture of early transcriptomic adaptation to Na2CO3 stress, and highlights potential molecular pathways that could be manipulated to improve tolerance in maize.

Zhang L-M, Liu X-G, Qu X-N, Yu Y, Han S-P, Dou Y, Xu Y-Y, Jing H-C, Hao D-Y (2013) Early transcriptomic adaptation to Na2CO3 stress altered the expression of a quarter \the total genes in the maize genome and exhibited shared and distinctive profiles with NaCl and high pH stresses. J. Integr. Plant Biol. 55(11), 1147–1165.

Abstract (Browse 1242)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
          Plant Reproduction Biology
MYB56 Encoding a R2R3 MYB Transcription Factor Regulates Seed Size in Arabidopsis thaliana
Author: Yanjie Zhang, Wanqi Liang, Jianxin Shi, Jie Xu and Dabing Zhang
Journal of Integrative Plant Biology 2013 55(11): 1166每1178
Published Online: September 9, 2013
DOI: 10.1111/jipb.12094

Plant seed size is tightly regulated by the development of seed coat, embryo, and endosperm; however, currently, its underlying mechanism remains unclear. In this study, we revealed a regulatory role of an R2R3 MYB transcription factor MYB56 in controlling seed size specifically in Arabidopsis thaliana L. Loss-of-function or knock-down of MYB56 yielded smaller seeds as compared with the wild type. Conversely, overexpression of MYB56 produced larger seeds. Further observation using semi-thin sections showed that myb56 developed smaller contracted endothelial cells and reduced cell number in the outer integument layer of the seed coat during the seed development; by contrast, MYB56 overexpressing lines had expanded endothelial cells and increased cell number in the outer integument layer of the seed coat, suggesting the essential role of MYB56 in regulating seed development. In addition, reciprocal cross-analysis showed that MYB56 affected the seed development maternally. MYB56 was shown to be dominantly expressed in developing seeds, consistently with its function in seed development. Moreover, quantitative reverse transcription polymerase chain reaction analysis revealed that MYB56 regulates the expression of genes involved in cell wall metabolism such as cell division and expansion. Altogether, our results demonstrated that MYB56 represents an unknown pathway for positively controlling the seed size.

Zhang Y, Liang W, Shi J, Xu J, Zhang D (2013) MYB56 encoding a R2R3 MYB transcription factor regulates seed size in Arabidopsis thaliana. J. Integr. Plant Biol. 55(11), 1166–1178.

Abstract (Browse 908)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Professor Ko Shimamoto (1949每2013)  
Author: Letian Chen, Yao-Guang Liu and William J. Lucas
Journal of Integrative Plant Biology 2013 55(11): 1179每1180
Published Online: October 30, 2013
DOI: 10.1111/jipb.12113
Abstract (Browse 1075)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       


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