Latest Accepted Articles

  Special Issue: Sexual Plant Reproduction
Suppression or knockout of SaF/SaM overcomes the Sa-mediated hybrid male sterility in rice
Author: Yongyao Xie, Baixiao Niu, Yunming Long, Gousi Li, Jintao Tang, Yaling Zhang, Ding Ren, Yao-Guang Liu and Letian Chen
Received: June 8, 2017         Accepted: June 19, 2017
Online Date: June 21, 2017
DOI: 10.1111/jipb.12564
                     
      
    

Hybrids between the indica and japonica subspecies of rice (Oryza sativa) are usually sterile, which hinders utilization of heterosis in the inter-subspecific hybrid breeding. The complex locus Sa comprises two adjacently located genes, SaF and SaM, which interact to cause abortion of pollen grains carrying the japonica allele in japonica-indica hybrids. Here we showed that silencing of SaF or SaM by RNA interference restored male fertility in indica-japonica hybrids with heterozygous Sa. We further used CRISPR/Cas9-based genome editing to knockout the SaF and SaM alleles respectively of an indica rice line to create hybrid-compatible lines. The resultant artificial neutral alleles did not affect pollen viability and other agricultural traits, but did break down the reproductive barrier in the hybrids. We found that some rice lines have natural neutral allele Sa-n, which was compatible with the typical japonica or indica Sa alleles in hybrids. Our results firmly proved that SaF and SaM are required for the hybrid male sterility, but are not essential for pollen development. This study provides effective approaches for the development of hybrid-compatible lines by knocking out the Sa locus or using the natural Sa-n allele to overcome hybrid male sterility in rice breeding.

Abstract (Browse 53)   |   Full Text
Arabidopsis shaker pollen inward K+ channel SPIK functions in SnRK1 complex-regulated pollen hydration on the stigma
Author: Dan-Dan Li, Huan Guan, Fei Li, Chang-Zhen Liu, Yu-Xiu Dong, Xian-Sheng Zhang and Xin-Qi Gao
Received: April 28, 2017         Accepted: June 19, 2017
Online Date: June 21, 2017
DOI: 10.1111/jipb.12563
                     
      
    

Pollen hydration is a critical step that determines pollen germination on stigma. KINβγ is a plant-specific subunit of the SNF1-related protein kinase 1 complex (SnRK1 complex). In pollen of the Arabidopsis kinβγ mutant, the levels of reactive oxygen species (ROS) were decreased which lead to compromised hydration of the mutant pollen on stigma. In this study, we analyzed gene expression in kinβγ mutant pollen by RNA-seq and found the expression of inward shaker K+ channel SPIK was down-regulated in the kinβγ pollen. Furthermore, we showed that the pollen hydration of the Arabidopsis spik mutant was defective on the wild-type stigma, although the mutant pollen demonstrated normal hydration in vitro. Additionally, the defective hydration of spik mutant pollen could not be rescued by the wild-type pollen on the stigma, indicating that the spik mutation deprived the capability of pollen absorption on the stigma. Our results suggest that the Arabidopsis SnRK1 complex regulates SPIK expression, which functions in determining pollen hydration on the stigma.

Abstract (Browse 45)   |   Full Text
ZYGOTE-ARREST 3 that encodes the tRNA ligase is essential for zygote division in Arabidopsis
Author: Ke-Jin Yang, Lei Guo, Xiu-Li Hou, Hua-Qin Gong and Chun-Ming Liu
Received: May 25, 2017         Accepted: June 16, 2017
Online Date: June 20, 2017
DOI: 10.1111/jipb.12561
                     
      
    

In sexual organisms, division of the zygote initiates a new life cycle. Although several genes involved in zygote division are known in plants, how the zygote is activated to start embryogenesis remains elusive. Here, we showed that a mutation in ZYGOTE-ARREST 3 (ZYG3) in Arabidopsis led to a tight zygote-lethal phenotype. Map-based cloning revealed that ZYG3 encodes the tRNA ligase AtRNL, which is a single-copy gene in the Arabidopsis genome. Expression analyses showed that AtRNL is expressed throughout zygotic embryogenesis, and in meristematic tissues. Using pAtRNL::cAtRNL-sYFP-complemented zyg3/zyg3 plants, we showed that AtRNL is localized exclusively in the cytoplasm, suggesting that tRNA splicing occurs primarily in the cytoplasm. Analyses using partially rescued embryos showed that mutation in AtRNL compromised splicing of intron-containing tRNA. Mutations of two tRNA endonuclease genes, SEN1 and SEN2, also led to a zygote-lethal phenotype. These results together suggest that tRNA splicing is critical for initiating zygote division in Arabidopsis.

Abstract (Browse 82)   |   Full Text
  Letters to the Editor
Seed dispersal by hornets: An unusual insect-plant mutualism
Author: Gao Chen, Zheng-Wei Wang, Yan Qin and Wei-Bang Sun
Received: June 15, 2017         Accepted: July 10, 2017
Online Date: July 11, 2017
DOI: 10.1111/jipb.12568
                     
      
    

Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms, and to date there are few records of this phenomenon. Through field investigations and behavioural assays conducted in four populations of Stemona tuberosa from 2011-2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in “long-distance” seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites. Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure “long-distance” seed dispersal in other myrmecochorous plants.

Abstract (Browse 27)   |   Full Text
THESEUS1 positively modulates plant defense responses against Botrytis cinerea through GUANINE EXCHANGE FACTOR4 signaling
Author: Shaofeng Qu, Xi Zhang, Yutong Song, Jinxing Lin and Xiaoyi Shan
Received: May 9, 2017         Accepted: June 21, 2017
Online Date: June 24, 2017
DOI: 10.1111/jipb.12565
                     
      
    

The plant cell wall is an important interface for sensing pathogen attack and activating signaling pathways that promote plant immune responses. THESEUS1 (THE1) acts as a sensor of cell wall integrity that controls cell elongation during plant growth. However, no specific role for THE1 in plant defense responses has been reported. Here, we found that THE1 interacts with GUANINE EXCHANGE FACTOR4 (GEF4) and that both proteins play regulatory roles in plant resistance to the necrotrophic fungus Botrytis cinerea (B. cinerea). Genetic analysis showed that THE1 and GEF4 function in the same genetic pathway to mediate plant defense responses. In addition, using transcriptome analysis, we identified various genes (such as defense-related, secondary metabolite-related, and transcription factor genes) that are likely downstream targets in the THE1-GEF4 signaling pathway. Our results suggest that THE1 functions as an upstream regulator of GEF4 signaling to positively regulate defense responses against B. cinerea in Arabidopsis.

Abstract (Browse 61)   |   Full Text
Arabidopsis TOR signaling is essential for sugar-regulated callus formation
Author: Kyounghee Lee and Pil Joon Seo
Received: May 10, 2017         Accepted: June 16, 2017
Online Date: June 17, 2017
DOI: 10.1111/jipb.12560
                     
      
    

Dedifferentiation is a remarkable process that produces pluripotent stem cells from differentiated somatic cells to ensure developmental plasticity. Plants have evolved the ability of cellular dedifferentiation, and signaling cascades related to auxin and cytokinin-dependent callus formation have been extensively investigated. However, the molecular mechanism underlying sugar-dependent callus formation remains unknown. Here, we found that sugar-dependent callus formation is mainly regulated by the TOR-E2Fa module in Arabidopsis. Sugar-activated TOR kinase phosphorylates and stabilizes E2Fa proteins to transcriptionally activate S-phase genes during callus formation. In parallel, E2Fa is transcriptionally regulated by the ARF-LBD transcription cascade. Multi-layered regulation of E2Fa by sugar and auxin is likely to shape balanced cellular dedifferentiation capability in Arabidopsis.

Abstract (Browse 85)   |   Full Text
Mutation in a novel gene SMALL AND CORDATE LEAF 1 affects leaf morhology in cucumber
Author: Dongli Gao, Chunzhi Zhang, Shu Zhang, Bowen Hu, Shenhao Wang, Zhonghua Zhang and Sanwen Huang
Received: May 12, 2017         Accepted: June 7, 2017
Online Date: June 9, 2017
DOI: 10.1111/jipb.12558
                     
      
    

Plant species exhibit substantial variation in leaf morphology. We isolated a recessive mutant gene termed small and cordate leaf 1 (scl1) that causes alteration in both leaf size and shape of cucumber. Compared to wild type leaves, scl1 mutant had less number of epidermal pavement cells. A single nucleotide polymorphism was associated with the leaf phenotype, which occurred in a putative nucleoside bisphosphate phosphatase. RNA-seq analysis of the wild type and scl1 mutant leaves suggested that SCL1 regulation may not involve known hormonal pathways. Our work identified a candidate gene for SCL1 that may play a role in leaf development.

Abstract (Browse 88)   |   Full Text
  Cell and Developmental Biology
ARR12 promotes de novo shoot regeneration in Arabidopsis thaliana via activation of WUSCHEL expression
Author: Xuehuan Dai, Zhenhua Liu, Meng Qiao, Juan Li, Shuo Li and Fengning Xiang
Received: May 6, 2017         Accepted: July 3, 2017
Online Date: July 5, 2017
DOI: 10.1111/jipb.12567
                     
      
    

Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully elucidated. Here, we describe the regulatory control of shoot regeneration in Arabidopsis thaliana (L.) Heynh, based on the interaction of ARABIDOPSIS RESPONSE REGULATOR12 (ARR12) and WUSCHEL (WUS). The major site of ARR12 expression coincided with the location where the shoot apical meristem (SAM) initiated. The arr12 mutants showed severely impaired shoot regeneration and reduced responsiveness to cytokinin; consistent with this, the overexpression of ARR12 enhanced shoot regeneration. Certain shoot meristem specification genes, notably WUSCHEL (WUS) and CLAVATA3, were significantly downregulated in the arr12 explants. Chromatin immunoprecipitation (ChIP) and transient activation assays demonstrated that ARR12 binds to the promoter of WUS. These observations indicate that during shoot regeneration in vitro, ARR12 functions as a molecular link between cytokinin signaling and the expression of shoot meristem specification genes.

Abstract (Browse 45)   |   Full Text
  Invited Expert Review
Small RNAs in regulating temperature stress response in plants
Author: Qing Liu, Shijuan Yan, Tifeng Yang, Shaohong Zhang, Yue-Qin Chen and Bin Liu
Received: July 5, 2017         Accepted: July 12, 2017
Online Date: July 21, 2017
DOI: 10.1111/jipb.12571
                     
      
    

Due to global climate change, temperature stress has become one of the primary causes of crop losses worldwide. Much progress has been made in unraveling the complex stress response mechanisms in plants, particularly in the identification of temperature stress responsive protein-coding genes. Recently discovered microRNAs (miRNAs) and endogenous small-interfering RNAs (siRNAs) have also been demonstrated as important players in plant temperature stress response. Using high-throughput sequencing, many small RNAs, especially miRNAs, have been identified to be triggered by cold or heat. Subsequently, several studies have shown an important functional role for these small RNAs in cold or heat tolerance. These findings greatly broaden our understanding of endogenous small RNAs in plant stress response control. Here, we highlight new findings regarding the roles of miRNAs and siRNAs in plant temperature stress response and acclimation. We also review current understanding of the regulatory mechanisms of small RNAs in temperature stress response, and explore the outlook for the utilization of these small RNAs in molecular breeding for improvement of temperature stress tolerance in plants.

Abstract (Browse 24)   |   Full Text
Engineering crop nutrient efficiency for sustainable agriculture
Author: Liyu Chen and Hong Liao
Received: February 27, 2017         Accepted: June 6, 2017
Online Date: June 10, 2017
DOI: 10.1111/jipb.12559
                     
      
    

Increasing crop yields can provide food, animal feed, bioenergy feedstocks, and biomaterials to meet increasing global demand; however, the methods used to increase yield can negatively affect sustainability. For example, application of excess fertilizer can generate and maintain high yields but also increases input costs and contributes to environmental damage through eutrophication, soil acidification, and air pollution. Improving crop nutrient efficiency can improve agricultural sustainability by increasing yield while decreasing input costs and harmful environmental effects. Here, we review the mechanisms of nutrient efficiency (primarily for nitrogen, phosphorus, potassium, and iron) and breeding strategies for improving this trait, along with the role of regulation of gene expression in enhancing crop nutrient efficiency to increase yields. We focus on the importance of root system architecture to improve nutrient acquisition efficiency, as well as the contributions of mineral translocation, remobilization, and metabolic efficiency to nutrient utilization efficiency.

Abstract (Browse 100)   |   Full Text
  Plant-environmental Interactions
Localized micronutrient patches induce lateral root foraging and chemotropism in Nicotiana attenuata
Author: Abigail P. Ferrieri, Ricardo A.R. Machado, Carla C.M. Arce, Danny Kessler, Ian T. Baldwin and Matthias Erb
Received: March 14, 2017         Accepted: June 23, 2017
Online Date: June 26, 2017
DOI: 10.1111/jipb.12566
                     
      
    

Nutrients are distributed unevenly in the soil. Phenotypic plasticity in root growth and proliferation may enable plants to cope with this variation and effectively forage for essential nutrients. However, how micronutrients shape root architecture of plants in their natural environments is poorly understood. We employed a combination of field and laboratory-based assays to determine the capacity of Nicotiana attenuata to direct root growth towards localized nutrient patches in its native environment. Plants growing in nature displayed a particular root phenotype consisting of a single primary root and a few long, shallow lateral roots. Analysis of bulk soil surrounding the lateral roots revealed a strong positive correlation between lateral root placement and micronutrient gradients, including copper, iron and zinc. In laboratory assays, the application of localized micronutrient salts close to lateral root tips led to roots bending in the direction of copper and iron. This form of chemotropism was absent in ethylene and jasmonic acid deficient lines, suggesting that it is controlled in part by these two hormones. This work demonstrates that directed root growth underlies foraging behavior, and suggests that chemotropism and micronutrient-guided root placement are important factors that shape root architecture in nature.

Abstract (Browse 43)   |   Full Text
  Plant Reproduction Biology
Arabidopsis CPR5 regulates ethylene signaling via molecular association with the ETR1 receptor
Author: Feifei Wang, Lijuan Wang, Longfei Qiao, Jiacai Chen, Maria Belen Pappa, Haixia Pei, Tao Zhang, Caren Chang and Chun-Hai Dong
Received: April 10, 2017         Accepted: June 26, 2017
Online Date: July 14, 2017
DOI: 10.1111/jipb.12570
                     
      
    

The plant hormone ethylene plays various functions in plant growth, development and response to environmental stress. Ethylene is perceived by membrane-bound ethylene receptors, and among the homologous receptors in Arabidopsis, the ETR1 ethylene receptor plays a major role. The present study provides evidence demonstrating that Arabidopsis CPR5 functions as a novel ETR1 receptor-interacting protein in regulating ethylene response and signaling. Yeast split ubiquitin assays and bi-fluorescence complementation studies in plant cells indicated that CPR5 directly interacts with the ETR1 receptor. Genetic analyses indicated that mutant alleles of cpr5 can suppress ethylene insensitivity in both etr1-1 and etr1-2, but not in other dominant ethylene receptor mutants. Overexpression of Arabidopsis CPR5 either in transgenic Arabidopsis plants, or ectopically in tobacco, significantly enhanced ethylene sensitivity. These findings indicate that CPR5 plays a critical role in regulating ethylene signaling. CPR5 is localized to endomembrane structures and the nucleus, and is involved in various regulatory pathways, including pathogenesis, leaf senescence, and spontaneous cell death. This study provides evidence for a novel regulatory function played by CPR5 in the ethylene receptor signaling pathway in Arabidopsis.

Abstract (Browse 25)   |   Full Text

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