Proteomic Analysis Reveals Proteins Involved in Seed Imbibition under Salt Stress in Rice.

Enshun Xu,Chengfang Zhan,Mingming Chen,Hongsheng Zhang,Yanhao Cheng,Hui He,Zhoufei Wang

doi:10.3389/fpls.2016.02006

Enshun Xu, Chengfang Zhan + Show 5 more

Open Access

https://doi.org/10.3389/fpls.2016.02006

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Abstract

Enhancement of salinity tolerance during seed germination is very important for direct seeding in rice. In this study, the salt-tolerant japonica landrace Jiucaiqing was used to determine the regulators that are involved in seed imbibition under salt stress. Briefly, the comparative proteomic analysis was conducted between dry (0 h) and imbibed (24 h) seeds with 150 mM NaCl. Under salt stress, the uptake of water increased rapidly before 24 h imbibition (Phase I), followed by a plateau of seed imbibition from 24 to 96 h imbibition (Phase II). We identified 14 proteins involved in seed imbibition, in which the majority of these proteins were involved in energy supply and storage protein. The early imbibition process was mediated by protein catabolism; the most of proteins were down-regulated after 24 h imbibition. Eleven genes in salt stress treated seeds were expressed early during the seed imbibition in comparison to control seeds. By comparison, 2,3-bisphosphoglycerate-independent phosphoglycerate mutase (BPM), glutelin (GLU2.2 and GLU2.3), glucose-1-phosphate adenylyltransferase large subunit (GAS8), and cupin domain containing protein (CDP3.1 and CDP3.2) were near the regions of quantitative trait loci (QTLs) for seed dormancy, seed reserve utilization, and seed germination in Jiucaiqing. In particular, CDP3.1 was co-located in the region of qIR-3 for imbibition rate, and qGP-3 for germination percentage. The role of CDP3.1 was verified in enhancing seed germination under salt stress using T-DNA mutant. The identified proteins might be applicable for the improvement of seed germination under salt stress in rice.

Highlights

Rice (Oryza sativa L.) is a salt-sensitive crop
During Phase II, the seeds radicles began to emerge after 36 h imbibition, and the maximum germination (99.3%) was attained after 96 h imbibition (Figure 1B)
The imbibed seeds in the early Phase II (24 h) of imbibition were collected for further proteomic analysis

Summary

Introduction

Rice (Oryza sativa L.) is a salt-sensitive crop. About 30% of the rice growing area in the world were affected by salinity (Takehisa et al, 2004) due to defective irrigation and fertilization (Lin et al, 2004). The direct seeding method recently has become increasingly important in many Asian countries due to its lower cost and operational simplicity (Fujino et al, 2004; Wang et al, 2011). Improving seed germination under salt stress is an important goal for rice breeding. Several proteomics analyses of seed germination had been applied in rice (Sano et al, 2012; Han et al, 2014a,b; Xu et al, 2016; Zhang et al, 2016)

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