Overexpression of the leucine-rich receptor-like kinase gene LRK2 increases drought tolerance and tiller number in rice.

Junfang Kang,Chao Tian,Xiaojun Zha,Shuang Gao,Jianmin Li

doi:10.1111/pbi.12707

Abstract

SummaryDrought represents a key limiting factor of global crop distribution. Receptor‐like kinases play major roles in plant development and defence responses against stresses such as drought. In this study, LRK2, which encodes a leucine‐rich receptor‐like kinase, was cloned and characterized and found to be localized on the plasma membrane in rice. Promoter–GUS analysis revealed strong expression in tiller buds, roots, nodes and anthers. Transgenic plants overexpressing LRK2 exhibited enhanced tolerance to drought stress due to an increased number of lateral roots compared with the wild type at the vegetative stage. Moreover, ectopic expression of LRK2 seedlings resulted in increased tiller development. Yeast two‐hybrid screening and bimolecular fluorescence complementation (BiFC) indicated a possible interaction between LRK2 and elongation factor 1 alpha (OsEF1A) in vitro. These results suggest that LRK2 functions as a positive regulator of the drought stress response and tiller development via increased branch development in rice. These findings will aid our understanding of branch regulation in other grasses and support improvements in rice genetics.

Highlights

Rice (Oryza sativa) is one of the most important crops, feeding more than one-third of the world’s population
Molecular genetic tools aimed at improving rice drought tolerance and maintaining production, while expanding development into regions with limited water resources is important (Fernie et al, 2006; Pennisi, 2008)
The overexpressing lines showed a slight increase in the number of secondary branches on the main panicle compared with the wild type (M2: 7.86%; M6: 6.46%); the number of primary branches did not significantly differ (Table 2, Figure S4C). These results suggest that LRK2 improves rice tiller number and the number of grains per plant

Summary

Introduction

Rice (Oryza sativa) is one of the most important crops, feeding more than one-third of the world’s population. This major staple requires large amounts of water during growth and is susceptible to drought stress. At least 223 LRKs are known in Arabidopsis and more than 300 in rice (Shiu et al, 2001). Known functions in rice remain limited to, for example, ERECTA (Shen et al, 2015), Xa21 (Jiang et al, 2013; Song et al, 1997), OsSIK1 (Ouyang et al, 2010) and FON1 (Feng et al, 2014), with the majority of genes yet to be elucidated

Results

Discussion

Conclusion