Parental Drought-Priming Enhances Tolerance to Post-anthesis Drought in Offspring of Wheat.

Qin Zhou,Jing Chen,Jian Cai,Dong Jiang,Xiao Wang,Tingbo Dai,Xiulin Wang,Weixing Cao,Xiaxiang Zhang

doi:10.3389/fpls.2018.00261

Abstract

Drought is the major abiotic stress that decreases plant water status, inhibits photosynthesis, induces oxidative stress, restricts growth and finally lead to the reduction of wheat yield. It has been proven that drought priming during vegetative growth stage could enhance tolerance to drought stress at grain filling in wheat. However, whether drought priming imposed at grain filling in parental plants could induce drought tolerance in the offspring is not known. In this study, drought priming was successively applied in the first, the second and the third generation of wheat to obtain the plants of T1 (primed for one generation), T2 (primed for two generations), T3 (primed for three generations). The differently primed plants were then subjected to drought stress during grain filling in the fourth generation. Under drought stress, the parentally primed (T1D, T2D, T3D) plants, disregarding the number of generations, showed higher grain yield, leaf photosynthetic rate and antioxidant capacity as well as lower release rate and contents of H2O2 and MDA than the non-primed (T0D) plants, suggesting that drought priming induced the transgenerational stress tolerance to drought stress. Moreover, the parentally primed plants showed higher leaf water status, which may result from the higher contents of proline and glycine betaine, and higher activities of Δ1-pyrroline-5-carboxylate synthetase (P5CS) and betaine aldehyde dehydrogenase (BADH), compared with the non-primed plants under drought stress. In addition, there was no significant difference among three generations under drought, and the drought priming in parental generations did not affect the grain yield of the offspring plants under control condition. Collectively, the enhanced accumulation of proline and glycine betaine in the parentally primed plants could have played critical roles in parental priming induced tolerance to drought stress. This research provided a potential approach to improve drought tolerance of offspring plants by priming parental plants.

Highlights

Drought is one of the critical environmental adversities affecting the growth, development and final yield of crop species (Geng et al, 2016; Daryanto et al, 2017), and the frequency and severity of drought stress events are expecting to increase due to global climate change (Cook et al, 2014; Zhao and Dai, 2015; Joshi et al, 2016)
The results suggested that drought priming during parental generation could induce drought tolerance of offspring in wheat, as exemplified by less reduction grain yield of the primed (T1D, T2D, T3D) plants compared with the non-primed (T0D) plants under drought, which may results from better maintenance of photosynthesis, greater antioxidant capacity and higher osmolytes accumulation in the primed plants
The activities of pyrroline-5-carboxylate synthetase (P5CS) increased and proline dehydrogenase (PDH) decreased, these could contribute to the accumulation of proline under drought stress

Summary

Introduction

Drought is one of the critical environmental adversities affecting the growth, development and final yield of crop species (Geng et al, 2016; Daryanto et al, 2017), and the frequency and severity of drought stress events are expecting to increase due to global climate change (Cook et al, 2014; Zhao and Dai, 2015; Joshi et al, 2016). Antioxidant enzymes mainly include superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX), and non-enzymatic antioxidants mainly include reduced ascorbate (AsA) and reduced glutathione (GSH) (Apel and Hirt, 2004; Miller et al, 2010) Another important biochemical response to drought is osmotic adjustment such as the accumulation of proline and glycine betaine (GB), which can help plants to retain or absorb more water by decreasing the osmotic potential of plant cells, buffer cellular redox potential and maintain the structure and physiological function of biological macromolecules (Hare et al, 1998; Sakamoto and Murata, 2002; Ashraf and Foolad, 2007; Szabados and Savoure, 2010; Wang et al, 2014a)

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Discussion

Conclusion