Activation of ABA Receptors Gene GhPYL9-11A Is Positively Correlated with Cotton Drought Tolerance in Transgenic Arabidopsis.

Chengzhen Liang,Waqas Malik,Muhammad Ali Abid,Sandui Guo,Yanyan Li,Guoqing Sun,Yan Liu,Zhigang Meng,Tao Zhu,Rui Zhang,Rong Yan,Yuan Wang,Shujing Kang

doi:10.3389/fpls.2017.01453

Abstract

The sensitivity to abscisic acid (ABA) by its receptors, pyrabactin resistance-like proteins (PYLs), is considered a most important factor in activating the ABA signal pathway in response to abiotic stress. However, it is still unknown which PYL is the crucial ABA receptor mediating response to drought stress in cotton (Gossypium hirsutum L.). Here, we reported the identification and characterization of highly induced ABA receptor GhPYL9-11A in response to drought in cotton. It is observed that GhPYL9-11A was highly induced by ABA treatment. GhPYL9-11A binds to protein phosphatase 2Cs (PP2Cs) in an ABA-independent manner. Moreover, the GhPYL-11A-PP2C interactions are partially disrupted by mutations, proline (P84) and histidine (H111), in the gate-latch region. Transgenic Arabidopsis overexpressing GhPYL9-11A plants were hypersensitive to ABA during seed germination and early seedling stage. Further, the increased in root growth and up regulation of drought stress-related genes in transgenic Arabidopsis as compared to wild type confirmed the potential role of GhPYL9-11A in abiotic stress tolerance. Consistently, the expression level of GhPYL9-11A is on average higher in drought-tolerant cotton cultivars than in drought-sensitive cottons under drought treatment. In conclusion, the manipulation of GhPYL9-11A expression could be a useful strategy for developing drought-tolerant cotton cultivars.

Highlights

Abscisic acid (ABA) is a multifunctional phytohormone that regulates multiple aspects of plant growth and development, including seed dormancy and germination (Fang et al, 2008), vegetative development (Finkelstein et al, 2002), root elongation (Xing et al, 2016), leaf senescence (Liang et al, 2014), and fruit ripening (Zhang et al, 2009)
All members of PYL9-I in both diploid and tetraploid cotton were highly expressed during seed germination and drought stress, whereas PLY9-II members were with low expression level (Table S2)
These results suggest that PYL9-I proteins may play important roles in the regulation of seed germination and drought responses in cotton

Summary

Introduction

Abscisic acid (ABA) is a multifunctional phytohormone that regulates multiple aspects of plant growth and development, including seed dormancy and germination (Fang et al, 2008), vegetative development (Finkelstein et al, 2002), root elongation (Xing et al, 2016), leaf senescence (Liang et al, 2014), and fruit ripening (Zhang et al, 2009). ABA-regulated stress responses include changes in gene expression, increased. Previous studies have demonstrated that pyrabactin resistance-like (PYL), clade A protein phosphatase 2C (PP2C), and sucrose non-fermenting 1- related protein kinase 2 (SnRK2) proteins are the three core components of the ABA signaling cascade (Park et al, 2009; Sheard and Zheng, 2009; Zhu, 2016). The primary step in initiating the ABA signaling pathway is triggered by the PYL ABA receptors (Sheard and Zheng, 2009), which contain a central hydrophobic ligand-binding pocket (Iyer et al, 2001). ABA-activated SnRK2 kinases subsequently phosphorylate and activate downstream ABAresponsive element-binding transcription factors that induce the expression of ABA-responsive genes (Melcher et al, 2009; Miyazono et al, 2009; Nishimura et al, 2009)

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Discussion

Conclusion