Yong Gao, Meiqin Wu, Mengjiao Zhang, Wei Jiang, Xiaoyun Ren, Enxing Liang, Dongping Zhang , Changquan Zhang, Ning Xiao, Yan Li, Yi Dai , Jianmin Chen,

Plant Biotechnology Journal: First published: 12 March 2018

Summary

Phytochrome‐interacting factors (PIFs) play major roles in regulating plant growth and development, but their roles in drought stress remain elusive. Here, we cloned and characterized a maize (Zea mays) PIF transcription factor, ZmPIF1. The expression level of ZmPIF1 was significantly induced by independent drought and abscisic acid (ABA) treatments. The ZmPIF1 transgenic rice and Arabidopsis displayed water saving and drought resistance, which were associated with reduced a stomatal aperture and transpiration rate. Moreover, the ZmPIF1 transgenic rice were hypersensitive to exogenous ABA, while the endogenous ABA level was not significantly changed, suggesting that ZmPIF1 was a positive regulator of the ABA signalling pathway. Digital gene expression (DGE) results further indicated that ZmPIF1 participated in ABA signalling pathway and regulated the stomatal aperture in rice. In addition, grain yield and agronomic traits analysis over 4 years showed that ZmPIF1 was able to increase the grain yield through an increase in tiller and panicle numbers in transgenic rice. Overall, ZmPIF1plays an important role in the ABA‐mediated regulation of stomatal closure to control water loss. ZmPIF1 can enhance water saving and drought resistance and improve the crop yield in rice, illustrating the capacity of ZmPIF1 for crop improvement.

See: https://onlinelibrary.wiley.com/doi/full/10.1111/pbi.12878

Figure 2: ZmPIF1 improves drought tolerance of transgenic rice. (a) Seedlings treated with 20% polyethylene glycol (PEG) (n = 32). Two‐week‐old rice seedlings of ZmPIF1 transgenic lines, wild‐type and vector controls were exposed to 20% PEG for 4 days and then allowed to recover for 10 days. Bar = 5 cm. (b) Survival rates of the transgenic and the control rice after PEG treatment. (c) Relative water content (RWC) (n = 20). (d) Chlorophyll content (n = 20). (e) Chlorophyll fluorescence (Fv/Fm) (n = 20). (f) Cell membrane stability (CMS) (n = 20). (c–f) Two‐week‐old rice seedlings were treated 20% PEG for 48 h. (g) ZmPIF1 transgenic rice have enhanced tolerance to drought in soil. Forty‐day‐old seedlings of ZmPIF1 transgenic rice, wild‐type and vector controls grown in soil subjected to drought stress for 7 days and then rewatered for 10 days. Bar = 5 cm. (h) Survival rates of transgenic and control rice after drought stress (n = 20–40). (b, h) Data represent the mean ± SD. (c–f) Data represent the mean ± SE. ** t‐test, with P < 0.01; *t‐test, with P < 0.05.