Early View

  Letter to the Editor
Jasmonate signaling makes flowers attractive to pollinators and repellant to florivores in nature
Author: Ran Li, Meredith C. Schuman, Yang Wang, Lucas Cortés Llorca, Julia Bing, Anne Bennion, Rayko Halitschke and Ian T. Baldwin
Received: August 19, 2017         Accepted: October 18, 2017
Online Date: October 23, 2017
DOI: 10.1111/jipb.12607

Flowers are required for the Darwinian fitness of flowering plants, but flowers’ advertisements for pollination services can attract florivores. Previous glasshouse work with Nicotiana attenuata revealed the role of jasmonate (JA) signaling in flower development, advertisement and defense. However, whether JA signaling mediates flowers’ filtering of floral visitors in nature remained unknown. This field study revealed that silencing JA signaling resulted in flowers that produce less nectar and benzyl acetone, two pollinator-attractive traits. Meanwhile, flowers of defenseless plants were highly attacked by a suite of native herbivores, and damage to buds in native plants correlated negatively with their JA-Ile levels.


Abstract (Browse 71)   |   References   |   Full Text HTML   |   Full Text PDF       
  Special Issue: Genomics-assisted Germplasm Improvement in Rice
The calcium-dependent kinase OsCPK24 functions in cold stress responses in rice
Author: Yu Liu, Chunjue Xu, Yanfen Zhu, Lina Zhang, Taiyu Chen, Fei Zhou, Hao Chen and Yongjun Lin
Received: August 2, 2017         Accepted: November 23, 2017
Online Date: November 29, 2017
DOI: 10.1111/jipb.12614

Calcium-dependent protein kinases (CPKs) are serine/threonine protein kinases that function in plant stress responses. Although CPKs are recognized as key messengers in signal transduction, the specific roles of CPKs and the molecular mechanisms underlying their activity remain largely unknown. Here, we characterized the function of OsCPK24, a cytosol-localized calcium-dependent protein kinase in rice. OsCPK24 was universally and highly expressed in rice plants and was induced by cold treatment. Whereas OsCPK24 knockdown plants exhibited increased sensitivity to cold compared to wild type (WT), OsCPK24-overexpressing plants exhibited increased cold tolerance. Plants overexpressing OsCPK24 exhibited increased accumulation of proline (an osmoprotectant) and glutathione (an antioxidant) and maintained a higher GSH/GSSG (reduced glutathione to oxidized glutathione) ratio during cold stress compared to WT. In addition to these effects in response to cold stress, we observed the kinase activity of OsCPK24 varied under different calcium concentrations. Further, OsCPK24 phosphorylated OsGrx10, a glutathione-dependent thioltransferase, at rates modulated by changes in calcium concentration. Together, our results support the hypothesis that OsCPK24 functions as a positive regulator of cold stress tolerance in rice, a process mediated by calcium signaling and involving phosphorylation and the inhibition of OsGrx10 to sustain higher glutathione levels.

Abstract (Browse 32)   |   References   |   Full Text HTML   |   Full Text PDF       
A substitution mutation in OsPELOTA confers bacterial blight resistance by activating the salicylic acid pathway  
Author: Xiao-Bo Zhang, Bao-Hua Feng, Hui-Mei Wang, Xia Xu, Yong-Feng Shi, Yan He, Zheng Chen, Atul Prakash Sathe, Lei Shi and Jian-Li Wu
Received: August 13, 2017         Accepted: November 24, 2017
Online Date: November 29, 2017
DOI: 10.1111/jipb.12613

We previously reported a spotted-leaf mutant pelota (originally termed HM47) in rice displaying arrested growth and enhanced resistance to multiple races of Xanthomonas oryzae pv. oryzae. Here, we report the map-based cloning of the causal gene OsPELOTA (originally termed splHM47). We identified a single base substitution from T to A at position 556 in the coding sequence of OsPELOTA, effectively mutating phenylalanine to isoleucine at position 186 in the translated protein sequence. Both functional complementation and over-expression could rescue the spotted-leaf phenotype. OsPELOTA, a paralogue to eukaryotic release factor 1 (eRF1), shows high sequence similarity to Drosophila Pelota and also localizes to the endoplasmic reticulum and plasma membrane. OsPELOTA is constitutively expressed in roots, leaves, sheaths, stems, and panicles. Elevated levels of salicylic acid and decreased level of jasmonate were detected in the pelota mutant. RNA-seq analysis confirmed that genes responding to salicylic acid were upregulated in the mutant. Our results indicate that the rice PELOTA protein is involved in bacterial leaf blight resistance by activating the salicylic acid metabolic pathway.

Abstract (Browse 54)   |   References   |   Full Text HTML   |   Full Text PDF       
Chromatin-remodeling factor OsINO80 is involved in regulation of gibberellin biosynthesis and is crucial for rice plant growth and development
Author: Chao Li, Yuhao Liu, Wen-Hui Shen, Yu Yu and Aiwu Dong
Received: September 27, 2017         Accepted: October 17, 2017
Online Date: October 17, 2017
DOI: 10.1111/jipb.12603

The phytohormone gibberellin (GA) plays essential roles in plant growth and development. Here, we report that OsINO80, a conserved ATP-dependent chromatin-remodeling factor in rice (Oryza sativa), functions in both GA biosynthesis and diverse biological processes. OsINO80-knockdown mutants, derived from either T-DNA insertion or RNA interference, display typical GA-deficient phenotypes, including dwarfism, reduced cell length, late flowering, retarded seed germination and impaired reproductive development. Consistently, transcriptome analyses reveal that OsINO80 knockdown results in downregulation by more than two-fold of over 1,000 genes, including the GA biosynthesis genes CPS1 and GA3ox2, and the dwarf phenotype of OsINO80-knockdown mutants can be rescued by the application of exogenous GA3. Chromatin immunoprecipitation (ChIP) experiments show that OsINO80 directly binds to the chromatin of CPS1 and GA3ox2 loci. Biochemical assays establish that OsINO80 specially interacts with histone variant H2A.Z and the H2A.Z enrichments at CPS1 and GA3ox2 are decreased in OsINO80-knockdown mutants. Thus, our study identified a rice chromatin-remodeling factor, OsINO80, and demonstrated that OsINO80 is involved in regulation of the GA biosynthesis pathway and plays critical functions for many aspects of rice plant growth and development.

Abstract (Browse 52)   |   References   |   Full Text HTML   |   Full Text PDF       
OsIDD2, a zinc finger and INDETERMINATE DOMAIN protein, regulates secondary cell wall formation
Author: Peng Huang, Hideki Yoshida, Kenji Yano, Shunsuke Kinoshita, Kyosuke Kawai, Eriko Koketsu, Masako Hattori, Sayaka Takehara, Ji Huang, Ko Hirano, Reynante Lacsamana Ordonio, Makoto Matsuoka and Miyako Ueguchi-Tanaka
Received: February 8, 2017         Accepted: May 29, 2017
Online Date: June 2, 2017
DOI: 10.1111/jipb.12557

Previously, we found 123 transcription factors (TFs) as candidate regulators of secondary cell wall (SCW) formation in rice by using phylogenetic and co-expression network analyses. Among them, we examined in this work the role of OsIDD2, a zinc finger and indeterminate domain (IDD) family TF. Its overexpressors showed dwarfism, fragile leaves, and decreased lignin content, which are typical phenotypes of plants defective in SCW formation, whereas its knockout plants showed slightly increased lignin content. The RNA-seq and quantitative reverse transcription polymerase chain reaction analyses confirmed that some lignin biosynthetic genes were downregulated in the OsIDD2-overexpressing plants, and revealed the same case for other genes involved in cellulose synthesis and sucrose metabolism. The transient expression assay using rice protoplasts revealed that OsIDD2 negatively regulates the transcription of genes involved in lignin biosynthesis, cinnamyl alcohol dehydrogenase 2 and 3 (CAD2 and 3), and sucrose metabolism, sucrose synthase 5 (SUS5), whereas an AlphaScreen assay, which can detect the interaction between TFs and their target DNA sequences, directly confirmed the interaction between OsIDD2 and the target sequences located in the promoter regions of CAD2 and CAD3. Based on these observations, we conclude that OsIDD2 is negatively involved in SCW formation and other biological events by downregulating its target genes.

Abstract (Browse 213)   |   References   |   Full Text HTML   |   Full Text PDF       
Ectopic expression of fungal EcGDH improves nitrogen assimilation and grain yield in rice
Author: Dongying Tang, Yuchong Peng, Jianzhong Lin, Changqing Du, Yuanzhu Yang, Dan Wang, Cong Liu, Lu Yan, Xiaoying Zhao, Xia Li, Liangbi Chen and Xuanming Liu
Received: December 28, 2016         Accepted: January 5, 2017
Online Date: January 6, 2017
DOI: 10.1111/jipb.12519

NADP(H)-dependent glutamate dehydrogenases (GDH) in lower organisms have stronger ammonium affinity than those in higher plants. Here we report that transgenic rice overexpressing the EcGDH from Eurotium cheralieri exhibited significantly enhanced aminating activities. Hydroponic and field tests showed that nitrogen assimilation efficiency and grain yields were markedly increased in these transgenic plants, especially at the low nitrogen conditions. These results suggest that EcGDH may have potential to be used to improve nitrogen assimilation and grain yield in rice.

Abstract (Browse 433)   |   References   |   Full Text HTML   |   Full Text PDF       
QTL editing confers opposing yield performance in different rice varieties
Author: Lan Shen, Chun Wang, Yaping Fu, Junjie Wang, Qing Liu, Xiaoming Zhang, Changjie Yan, Qian Qian and Kejian Wang
Received: June 1, 2016         Accepted: September 13, 2016
Online Date: September 15, 2016
DOI: 10.1111/jipb.12501

Grain yield is one of the most important and complex trait for genetic improvement in crops; it is known to be controlled by a number of genes known as quantitative trait loci (QTLs). In the past decade, many yield-contributing QTLs have been identified in crops. However, it remains unclear whether those QTLs confer the same yield performance in different genetic backgrounds. Here, we performed CRISPR/Cas9-mediated QTL editing in five widely-cultivated rice varieties and revealed that the same QTL can have diverse, even opposing, effects on grain yield in different genetic backgrounds.

Abstract (Browse 488)   |   References   |   Full Text HTML   |   Full Text PDF       
  New Resources
Establishment and evaluation of a peanut association panel and analysis of key nutritional traits
Author: Xiurong Zhang, Suqing Zhu, Kun Zhang, Yongshan Wan, Fengzhen Liu, Qingfang Sun and Yingjie Li
Received: July 3, 2017         Accepted: September 29, 2017
Online Date: October 4, 2017
DOI: 10.1111/jipb.12601

Breeding programs aim to improve the yield and quality of peanut (Arachis hypogaea L.); using association mapping to identify genetic markers linked to these quantitative traits could facilitate selection efficiency. A peanut association panel was established consisting of 268 lines with extensive phenotypic and genetic variation, meeting the requirements for association analysis. These lines were grown over 3 years and the key agronomic traits, including protein and oil content were examined. Population structure (Q) analysis showed two subpopulations and clustering analysis was consistent with Q-based membership assignment and closely related to botanical type. Relative Kinship (K) indicated that most of the panel members have no or weak familial relatedness, with 52.78% of lines showing K = 0. Linkage disequilibrium (LD) analysis showed a high level of LD occurs in the panel. Model comparisons indicated false positives can be effectively controlled by taking Q and K into consideration and more false positives were generated by K than Q. A preliminary association analysis using a Q + K model found markers significantly associated with oil, protein, oleic acid, and linoleic acid, and identified a set of alleles with positive and negative effects. These results show that this panel is suitable for association analysis, providing a resource for marker-assisted selection for peanut improvement.

Abstract (Browse 70)   |   References   |   Full Text HTML   |   Full Text PDF       
  Plant-abiotic Interactions
Nicotiana attenuata's capacity to interact with arbuscular mycorrhiza alters its competitive ability and elicits major changes in the leaf transcriptome
Author: Ming Wang, Julia Wilde, Ian T. Baldwin and Karin Groten
Received: October 17, 2017         Accepted: October 27, 2017
Online Date: October 31, 2017
DOI: 10.1111/jipb.12609

To study the local and systemic effects of arbuscular mycorrhizal fungal (AMF) colonization, Nicotiana attenuata plants impaired in their interactions with AMF due to silencing of a calcium- and calmodulin dependent protein kinase (inverted repreat (ir)CCaMK) were grown competitively in pairs with empty vector (EV) plants, with and without two different types of inoculum. When inoculated, EV plants strongly outperformed irCCaMK plants. Foliar transcript profiling revealed that AMF colonization significantly changed gene expression of P-starvation and -transporter genes in irCCaMK plants. The Pht1 family phosphate transporter NaPT5 was not only specifically induced in roots after AMF colonization, but also in leaves of AMF-colonized irCCaMK plants, and in plants grown under low Pi conditions in the absence of AMF. The P-starvation signature of inoculated irCCaMK plants corresponded with increases in selected amino acids and phenolic compounds in leaves. We also found a strong AMF-induced increase in amino acids and phenolic metabolites in roots. Plants impaired in their interactions with AMF clearly have a fitness disadvantage when competing for limited soil nutrients with a fully functional isogenic line. The additional role of the AMF-induced Pht1 family transporter NaPT5 in leaves under P-starvation conditions will require further experiments to fully resolve.

Abstract (Browse 47)   |   References   |   Full Text HTML   |   Full Text PDF       
Characterization of the soybean GmALMT family genes and the function of GmALMT5 in response to phosphate starvation
Author: Wenting Peng, Weiwei Wu, Junchu Peng, Jiaojiao Li, Yan Lin, Yanan Wang, Jiang Tian, Lili Sun, Cuiyue Liang and Hong Liao
Received: August 27, 2017         Accepted: October 16, 2017
Online Date: October 17, 2017
DOI: 10.1111/jipb.12604

A potential mechanism to enhance utilization of sparingly soluble forms of phosphorus (P) is the root secretion of malate, which is mainly mediated by the ALMT gene family in plants. In this study, a total of 34 GmALMT genes were identified in the soybean genome. Expression patterns diverged considerably among GmALMTs in response to phosphate (Pi) starvation in leaves, roots and flowers, with expression altered by P availability in 26 of the 34 GmALMTs. One root-specific GmALMT whose expression was significantly enhanced by Pi-starvation, GmALMT5, was studied in more detail to determine its possible role in soybean P nutrition. Analysis of GmALMT5 tissue expression patterns, subcellular localization, and malate exudation from transgenic soybean hairy roots overexpressing GmALMT5, demonstrated that GmALMT5 is a plasma membrane protein that mediates malate efflux from roots. Furthermore, both growth and P content of transgenic Arabidopsis overexpressing GmALMT5 were significantly increased when sparingly soluble Ca-P was used as the external P source. Taken together, these results indicate that members of the soybean GmALMT gene family exhibit diverse responses to Pi starvation. One member of this family, GmALMT5, might contribute to soybean P efficiency by enhancing utilization of sparingly soluble P sources under P limited conditions.

Abstract (Browse 64)   |   References   |   Full Text HTML   |   Full Text PDF       
  Molecular Physiology
Quantitative trait loci associated with soybean seed weight and composition under different phosphorus levels
Author: Gokhan Hacisalihoglu, Amy L. Burton, Jeffery L. Gustin, Selim Eker, Safiye Asikli, Elif Hakli Heybet, Levent Ozturk, Ismail Cakmak, Atilla Yazici, Kent O. Burkey, James Orf and A. Mark Settles
Received: October 3, 2017         Accepted: November 10, 2017
Online Date: November 13, 2017
DOI: 10.1111/jipb.12612

Seed size and composition are important traits in food crops and can be affected by nutrient availability in the soil. Phosphorus (P) is a non-renewable, essential macronutrient, and P deficiency limits soybean (Glycine max) yield and quality. To investigate the associations of seed traits in low- and high-P environments, soybean recombinant inbred lines (RILs) from a cross of cultivars Fiskeby III and Mandarin (Ottawa) were grown under contrasting P availability environments. Traits including individual seed weight, seed number, and intact mature pod weight were significantly affected by soil P levels and showed transgressive segregation among the RILs. Surprisingly, P treatments did not affect seed composition or weight, suggesting that soybean maintains sufficient P in seeds even in low-P soil. Quantitative trait loci (QTLs) were detected for seed weight, intact pods, seed volume, and seed protein, with five significant QTLs identified in low-P environments and one significant QTL found in the optimal-P environment. Broad-sense heritability estimates were 0.78 (individual seed weight), 0.90 (seed protein), 0.34 (seed oil), and 0.98 (seed number). The QTLs identified under low P point to genetic regions that may be useful to improve soybean performance under limiting P conditions.

Abstract (Browse 49)   |   References   |   Full Text HTML   |   Full Text PDF       


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