December 2015, Volume 57 Issue 12, Pages 994每1098.


Cover Caption: PCD and Seed Structural Diversification
The time of PCD execution in nucellus and endosperm during seed development helps to explain the coexistence of endospermic and exendospermic species within the family of Leguminosae, or species with and without perisperm in the family of Chenopodiaceae. The cover shows middle longitudinal sections of castor, quinoa, maize and chayote seeds (see pp. 996每1002 for details).

 

          Minireview
Programmed cell death in seeds of angiosperms
Author: María Paula López-Fernóndez and Sara Maldonado
Journal of Integrative Plant Biology 2015 57(12): 996每1002
Published Online: May 7, 2015
DOI: 10.1111/jipb.12367
      
    
During the diversification of angiosperms, seeds have evolved structural, chemical, molecular and physiologically developing changes that specially affect the nucellus and endosperm. All through seed evolution, programmed cell death (PCD) has played a fundamental role. However, examples of PCD during seed development are limited. The present review examines PCD in integuments, nucellus, suspensor and endosperm in those representative examples of seeds studied to date.

 

López-Fernández MP, Maldonado S (2015) Programmed cell death in seeds of angiosperms. J Integr Plant Biol 57: 996–1002 doi: 10.1111/jipb.12367

 

Abstract (Browse 773)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Cell death occurs during development of a seed from an ovule. As the embryo and endosperm grow and develop, cells of ovular tissue die, some leaving their dead bodies, sometimes not. Timing and type of death vary in different species of Angiosperms. In this review we examine and compare PCD during seed development.
          Cell and Developmental Biology
ABORTED GAMETOPHYTE 1 is required for gametogenesis in Arabidopsis
Author: Hong-Hui Cui, Hong-Ze Liao, Yu Tang, Xin-Yu Du, Li-Qun Chen, De Ye and Xue-Qin Zhang
Journal of Integrative Plant Biology 2015 57(12): 1003每1016
Published Online: February 18, 2015
DOI: 10.1111/jipb.12341
      
    

In flowering plants, the male and female gametogenesis is a crucial step of sexual reproduction. Although many genes have been identified as being involved in the gametogenesis process, the genetic mechanisms underlying gametogenesis remains poorly understood. We reported here characterization of the gene, ABORTED GAMETOPHYTE 1 (AOG1) that is newly identified as essential for gametogenesis in Arabidopsis thaliana. AOG1 is expressed predominantly in reproductive tissues including the developing pollen grains and ovules. The AOG1 protein shares no significant amino acid sequence similarity with other documented proteins and is located mainly in nuclei of the cells. Mutation in AOG1 caused degeneration of pollen at the uninucleate microspore stage and severe defect in embryo sacs, leading to a significant reduction in male and female fertility. Furthermore, the molecular analyses showed that the aog1 mutant significantly affected the expression of several genes, which are required for gametogenesis. Our results suggest that AOG1 plays important roles in gametogenesis at the stage prior to pollen mitosis I (PMI) in Arabidopsis, possibly through collaboration with other genes.

 

Cui HH, Liao HZ, Tang Y, Du XY, Chen LQ, Ye D, Zhang XQ (2015) ABORTED GAMETOPHYTE 1 is required for gametogenesis in Arabidopsis. J Integr Plant Biol 57: 1003–1016 doi: 10.1111/jipb.12341

Abstract (Browse 847)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Mutation in AOG1 caused severe defects in pollen grains and embryo sacs, leading to a significant reduction in fertility. Therefore, AOG1 is essential for gametogenesis in Arabidopsis thaliana.
Activated expression of AtEDT1/HDG11 promotes lateral root formation in Arabidopsis mutant edt1 by upregulating jasmonate biosynthesis
Author: Xiao-Teng Cai, Ping Xu, Yao Wang and Cheng-Bin Xiang
Journal of Integrative Plant Biology 2015 57(12): 1017每1030
Published Online: March 4, 2015
DOI: 10.1111/jipb.12347
      
    

Root architecture is crucial for plants to absorb water and nutrients. We previously reported edt1 (edt1D) mutant with altered root architecture that contributes significantly to drought resistance. However, the underlying molecular mechanisms are not well understood. Here we report one of the mechanisms underlying EDT1/HDG11-conferred altered root architecture. Root transcriptome comparison between the wild type and edt1D revealed that the upregulated genes involved in jasmonate biosynthesis and signaling pathway were enriched in edt1D root, which were confirmed by quantitative RT-PCR. Further analysis showed that EDT1/HDG11, as a transcription factor, bound directly to the HD binding sites in the promoters of AOS, AOC3, OPR3, and OPCL1, which encode four key enzymes in JA biosynthesis. We found that the jasmonic acid level was significantly elevated in edt1D root compared with that in the wild type subsequently. In addition, more auxin accumulation was observed in the lateral root primordium of edt1D compared with that of wild type. Genetic analysis of edt1D opcl1 double mutant also showed that HDG11 was partially dependent on JA in regulating LR formation. Taken together, overexpression of EDT1/HDG11 increases JA level in the root of edt1D by directly upregulating the expressions of several genes encoding JA biosynthesis enzymes to activate auxin signaling and promote lateral root formation.

 

Cai XT, Xu P, Wang Y, Xiang CB (2015) Activated expression of AtEDT1/HDG11 promotes lateral root formation in Arabidopsis mutant edt1 by upregulating jasmonate biosynthesis. J Integr Plant Biol 57: 1017–1030 doi: 10.1111/jipb.12347

Abstract (Browse 826)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Homeodomain transcription factor EDT1 activates AOS, AOC3, OPR3, and OPCL1, encoding four key enzymes in jasmonic acid biosynthesis in Arabidopsis, and therefore elevates the content of jasmonic acid in the root of edt1D mutant. Consequently, auxin homeostasis is altered and lateral root formation is increased.
          Functional Omics and Systems Biology
Differential transcriptome analysis between Populus and its synthesized allotriploids driven by second-division restitution
Author: Shiping Cheng, Zhen Huang, Yun Li, Ting Liao, Yujing Suo, Pingdong Zhang, Jun Wang and Xiangyang Kang
Journal of Integrative Plant Biology 2015 57(12): 1031每1045
Published Online: December 30, 2014
DOI: 10.1111/jipb.12328
      
    

In this report, we compared transcriptomic differences between a synthetic Populus section Tacamahaca triploid driven by second-division restitution and its parents using a high-throughput RNA-seq method. A total of 4,080 genes were differentially expressed between the high-growth vigor allotriploids (SDR-H) and their parents, and 719 genes were non-additively expressed in SDR-H. Differences in gene expression between the allotriploid and male parent were more significant than those between the allotriploid and female parent, which may be caused by maternal effects. We observed 3,559 differentially expressed genes (DEGs) between the SDR-H and male parent. Notably, the genes were mainly involved in metabolic process, cell proliferation, DNA methylation, cell division, and meristem and developmental growth. Among the 1,056 DEGs between SDR-H and female parent, many genes were associated with metabolic process and carbon utilization. In addition, 1,789 DEGs between high- and low-growth vigor allotriploid were mainly associated with metabolic process, auxin poplar transport, and regulation of meristem growth. Our results indicated that the higher poplar ploidy level can generate extensive transcriptomic diversity compared with its parents. Overall, these results increased our understanding of the driving force for phenotypic variation and adaptation in allopolyploids driven by second-division restitution.

 

Cheng S, Huang Z, Li Y, Liao T, Suo Y, Zhang P, Wang J, Kang X (2015) Differential transcriptome analysis between Populus and its synthesized allotriploids driven by second-division restitution. J Integr Plant Biol 57: 1031–1045 doi: 10.1111/jipb.12328

Abstract (Browse 954)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Populus allotriploid has considerable effects on duplicate gene expression, and these genes participate in apical growth. Additionally, triploid hybrids exhibiting high-and low-growth phenotypes differ in terms of gene expression.
Quantitative trait locus mapping with background control in genetic populations of clonal F1 and double cross  
Author: Luyan Zhang, Huihui Li, Junqiang Ding, Jianyu Wu and Jiankang Wang
Journal of Integrative Plant Biology 2015 57(12): 1046每1062
Published Online: April 17, 2015
DOI: 10.1111/jipb.12361
      
    

In this study, we considered five categories of molecular markers in clonal F1 and double cross populations, based on the number of distinguishable alleles and the number of distinguishable genotypes at the marker locus. Using the completed linkage maps, incomplete and missing markers were imputed as fully informative markers in order to simplify the linkage mapping approaches of quantitative trait genes. Under the condition of fully informative markers, we demonstrated that dominance effect between the female and male parents in clonal F1 and double cross populations can cause the interactions between markers. We then developed an inclusive linear model that includes marker variables and marker interactions so as to completely control additive effects of the female and male parents, as well as the dominance effect between the female and male parents. The linear model was finally used for background control in inclusive composite interval mapping (ICIM) of quantitative trait locus (QTL). The efficiency of ICIM was demonstrated by extensive simulations and by comparisons with simple interval mapping, multiple-QTL models and composite interval mapping. Finally, ICIM was applied in one actual double cross population to identify QTL on days to silking in maize.

 

Zhang L, Li H, Ding J, Wu J, Wang J (2015) Quantitative trait locus mapping with background control in genetic populations of clonal F1 and double cross. J Integr Plant Biol 57: 1046–1062 doi: 10.1111/jipb.12361

Abstract (Browse 914)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
A novel method of genetic analysis was proposed to map quantitative trait genes in clonal species. Efficiency of this method was demonstrated by statistic principles, extensive simulations and comparisons with other methods. The method is also applicable to genetic populations derived from four inbred parental lines of sexual species.
          Molecular Physiology
Loss-of-function mutation of rice SLAC7 decreases chloroplast stability and induces a photoprotection mechanism in rice  
Author: Xiaolei Fan, Jiemin Wu, Taiyu Chen, Weiwei Tie, Hao Chen, Fei Zhou and Yongjun Lin
Journal of Integrative Plant Biology 2015 57(12): 1063每1077
Published Online: March 4, 2015
DOI: 10.1111/jipb.12350
      
    
Plants absorb sunlight to power the photochemical reactions of photosynthesis, which can potentially damage the photosynthetic machinery. However, the mechanism that protects chloroplasts from the damage remains unclear. In this work, we demonstrated that rice (Oryza sativa L.) SLAC7 is a generally expressed membrane protein. Loss-of-function of SLAC7 caused continuous damage to the chloroplasts of mutant leaves under normal light conditions. Ion leakage indicators related to leaf damage such as H2O2 and abscisic acid levels were significantly higher in slac7-1 than in the wild type. Consistently, the photosynthesis efficiency and Fv/Fm ratio of slac7-1 were significantly decreased (similar to photoinhibition). In response to chloroplast damage, slac7-1 altered its leaf morphology (curled or fused leaf) by the synergy between plant hormones and transcriptional factors to decrease the absorption of light, suggesting that a photoprotection mechanism for chloroplast damage was activated in slac7-1. When grown in dark conditions, slac7-1 displayed a normal phenotype. SLAC7 under the control of the AtSLAC1 promoter could partially complement the phenotypes of Arabidopsis slac1 mutants, indicating a partial conservation of SLAC protein functions. These results suggest that SLAC7 is essential for maintaining the chloroplast stability in rice.

 

Fan X, Wu J, Chen T, Tie W, Chen H, Zhou F, Lin Y (2015) Loss-of-function mutation of rice SLAC7 decreases chloroplast stability and induces a photoprotection mechanism in rice. J Integr Plant Biol 57: 1063–1077 doi: 10.1111/jipb.12350

Abstract (Browse 1064)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
SLAC7 is a membrane protein which is essential for maintaining the anion balance in rice. Its loss-of-function caused a continuous decrease of chloroplast stability and photoinhibition phenotypes. The leaf morphology of the SLAC7 mutant was altered by the synergy between hormones and transcriptional factors due to decreased light absorption.
Overexpression of potato miR482e enhanced plant sensitivity to Verticillium dahliae infection  
Author: Liu Yang, Xiaoying Mu, Chao Liu, Jinghui Cai, Ke Shi, Wenjiao Zhu and Qing Yang
Journal of Integrative Plant Biology 2015 57(12): 1078每1088
Published Online: March 4, 2015
DOI: 10.1111/jipb.12348
      
    

Verticillium wilt of potato is caused by the fungus pathogen Verticillium dahliae. Present sRNA sequencing data revealed that miR482 was in response to V. dahliae infection, but the function in potato is elusive. Here, we characterized potato miR482 family and its putative role resistance to Verticillium wilt. Members of the potato miR482 superfamily are variable in sequence, but all variants target a class of disease-resistance proteins with nucleotide binding site (NBS) and leucine-rich repeat (LRR) motifs. When potato plantlets were infected with V. dahliae, the expression level of miR482e was downregulated, and that of several NBS-LRR targets of miR482e were upregulated. Transgenic potato plantlets overexpressing miR482e showed hypersensitivity to V. dahliae infection. Using sRNA and degradome datasets, we validated that miR482e targets mRNAs of NBS-LRR disease-resistance proteins and triggers the production of trans-acting (ta)-siRNAs, most of which target mRNAs of defense-related proteins. Thus, the hypersensitivity of transgenic potato could be explained by enhanced miR482e and miR482e-derived ta-siRNA-mediated silencing on NBS-LRR-disease-resistance proteins. It is speculated that a miR482-mediated silencing cascade mechanism is involved in regulating potato resistance against V. dahliae infection and could be a counter defense action of plant in response to pathogen infection.

 

Yang L, Mu X, Liu C, Cai J, Shi K, Zhu W, Yang Q (2015) Overexpression of potato miR482e enhanced plant sensitivity to Verticillium dahliae infection. J Integr Plant Biol 57: 1078–1088 doi: 10.1111/jipb.12348

Abstract (Browse 1168)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Verticillium dalihae is the pathogen of Verticillium wilt, which spreads worldwide and causes serious economic loss for many cultivars. Here we found a potato miRNA, stu-miR482, which targets disease resistance proteins by silencing cascade, and presented a counter defense action of potato in response to Verticillium dahliae infection.
          Plant Reproduction Biology
ABCB1 and ABCB19 auxin transporters have synergistic effects on early and late Arabidopsis anther development  
Author: Valentina Cecchetti, Patrizia Brunetti, Nadia Napoli, Laura Fattorini, MariaMaddalena Altamura, Paolo Costantino and Maura Cardarelli
Journal of Integrative Plant Biology 2015 57(12): 1089每1098
Published Online: January 27, 2015
DOI: 10.1111/jipb.12332
      
    

Arabidopsis abcb1 abcb19 double mutants defective in the auxin transporters ABCB1/PGP1 and ABCB19/PGP19 are altered in stamen elongation, anther dehiscence and pollen maturation. To assess the contribution of these transporters to stamen development we performed phenotypic, histological analyses, and in situ hybridizations on abcb1 and abcb19 single mutant flowers. We found that pollen maturation and anther dehiscence are precocious in the abcb1 but not in the abcb19 mutant. Accordingly, endothecium lignification is altered only in abcb1 anthers. Both abcb1 and abcb1 abcb19 stamens also show altered early development, with asynchronous anther locules and a multilayer tapetum. DAPI staining showed that the timing of meiosis is asynchronous in abcb1 abcb19 anther locules, while only a small percentage of pollen grains are non-viable according to Alexander's staining. In agreement, TAM (TARDY ASYNCHRONOUS MEIOSIS), as well as BAM2 (BARELY ANY MERISTEM)—involved in tapetal cell development—are overexpressed in abcb1 abcb19 young flower buds. Correspondingly, ABCB1 and ABCB19 mRNA localization supports the observed phenotypes of abcb1 and abcb1 abcb19 mutant anthers. In conclusion, we provide evidence that auxin transport plays a significant role both in early and late stamen development: ABCB1 plays a major role during anther development, while ABCB19 has a synergistic role.

 

Cecchetti V, Brunetti P, Napoli N, Fattorini L, Altamura MM, Costantino P, Cardarelli M (2015) ABCB1 and ABCB19 auxin transporters have synergistic effects on early and late Arabidopsis anther development. J Integr Plant Biol 57: 1089–1098 doi: 10.1111/jipb.12332

Abstract (Browse 1005)  |  References  |  Full Text HTML  |  Full Text PDF  |  Cited By       
Proper development of the male reproductive organ (stamen) is necessary for plant fertility, and is controlled by auxin. We show that the transport of auxin by the ABCB1 and ABC19 proteins is required throughout stamen development for pollen maturation and the timely release of pollen grains in Arabidopsis thaliana.
 

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