Overexpression of V-type H+ pyrophosphatase gene EdVP1 from Elymus dahuricus increases yield and potassium uptake of transgenic wheat under low potassium conditions

Creating Climate-Resilient Crops by Increasing Drought, Heat, and Salt Tolerance

Over the years, the changes in the agriculture industry have been inevitable, considering the need to feed the growing population. As the world population continues to grow, food security has become challenged. Resources such as arable land and freshwater have become scarce due to quick urbanization in developing countries and anthropologic activities; expanding agricultural production areas is not an option. Environmental and climatic factors such as drought, heat, and salt stresses pose serious threats to food production worldwide. Therefore, the need to utilize the remaining arable land and water effectively and efficiently and to maximize the yield to support the increasing food demand has become crucial. It is essential to develop climate-resilient crops that will outperform traditional crops under any abiotic stress conditions such as heat, drought, and salt, as well as these stresses in any combinations. This review provides a glimpse of how plant breeding in agriculture has evolved to overcome the harsh environmental conditions and what the future would be like.

Overexpression of the autophagy-related gene SiATG8a from foxtail millet (Setaria italica L.) in transgenic wheat confers tolerance to phosphorus starvation

In plants, autophagy plays an important role in regulating intracellular degradation and amino acid recycling in response to nutrient starvation, senescence, and other environmental stresses. Foxtail millet (Setaria italica) shows strong resistance to various abiotic stresses; however, current understanding of the regulation network of abiotic stress resistance in foxtail millet remains limited. In this study, we aimed to determine the autophagy-related gene SiATG8a in foxtail millet. We found that SiATG8a was mainly expressed in the stem and was induced by low-phosphorus (LP) stress. Overexpression of SiATG8a in wheat (Triticum aestivum) significantly increased the grain yield and spike number per m² under LP treatment compared to those in the WT varieties S366 and S4056. There was no significant difference in the grain P content between SiATG8a-overexpressing wheat and WT wheat under normal phosphorus (NP) and LP treatments. However, the phosphorus (P) content in the roots, stems, and leaves of transgenic plants was significantly higher than that in WT plants under NP and LP conditions. Furthermore, the expression of P transporter genes, such as TaPHR1, TaPHR3, TaIPS1, and TaPT9, in SiATG8a-transgenic wheat was higher than that in WT under LP. Collectively, overexpression of SiATG8a increases the P content of roots, stems, and leaves of transgenic wheat under LP conditions by modulating the expression of P-related transporter gene, which may result in increased grain yield; thus, SiATG8a is a candidate gene for generating transgenic wheat with improved tolerance to LP stress in the field.

H+-pyrophosphatases enhance low nitrogen stress tolerance in transgenic Arabidopsis and wheat by interacting with a receptor-like protein kinase

INTRODUCTION

Nitrogen is a major abiotic stress that affects plant productivity. Previous studies have shown that plant H+-pyrophosphatases (H+-PPases) enhance plant resistance to low nitrogen stress. However, the molecular mechanism underlying H+-PPase-mediated regulation of plant responses to low nitrogen stress is still unknown. In this study, we aimed to investigate the regulatory mechanism of AtAVP1 in response to low nitrogen stress.

METHODS AND RESULTS

AtAVP1 in Arabidopsis thaliana and EdVP1 in Elymus dahuricus belong to the H+-PPase gene family. In this study, we found that AtAVP1 overexpression was more tolerant to low nitrogen stress than was wild type (WT), whereas the avp1-1 mutant was less tolerant to low nitrogen stress than WT. Plant height, root length, aboveground fresh and dry weights, and underground fresh and dry weights of EdVP1 overexpression wheat were considerably higher than those of SHI366 under low nitrogen treatment during the seedling stage. Two consecutive years of low nitrogen tolerance experiments in the field showed that grain yield and number of grains per spike of EdVP1 overexpression wheat were increased compared to those in SHI366, which indicated that EdVP1 conferred low nitrogen stress tolerance in the field. Furthermore, we screened interaction proteins in Arabidopsis; subcellular localization analysis demonstrated that AtAVP1 and Arabidopsis thaliana receptor-like protein kinase (AtRLK) were located on the plasma membrane. Yeast two-hybrid and luciferase complementary imaging assays showed that the AtRLK interacted with AtAVP1. Under low nitrogen stress, the Arabidopsis mutants rlk and avp1-1 had the same phenotypes.

DISCUSSION

These results indicate that AtAVP1 regulates low nitrogen stress responses by interacting with AtRLK, which provides a novel insight into the regulatory pathway related to H+-pyrophosphatase function in plants.

Functional characterization of BdCIPK31 in plant response to potassium deficiency stress

Potassium (K) is one of the most essential macronutrients for plants. However, K+ is deficient in some cultivated soils. Hence, improving the efficiencies of K+ uptake and utilization is important for agricultural production. Ca2+ signaling pathways play an important role in regulation of K+ acquisition. In the present study, BdCIPK31, a Calcineurin B-like protein interacting protein kinase (CIPK) from Brachypodium distachyon, was found to be a potential positive regulator in plant response to low K+ stress. The expression of BdCIPK31 was responsive to K+-deficiency, and overexpression of BdCIPK31 conferred enhanced tolerance to low K+ stress in transgenic tobaccos. Furthermore, BdCIPK31 was demonstrated to promote the K+ uptake in root, and could maintain normal root growth under K+-deficiency conditions. Additionally, BdCIPK31 functioned in scavenging excess reactive oxygen species (ROS), reduced oxidative damage caused by low K+ stress. Collectively, our study indicates that BdCIPK31 is a vital regulatory component in K+-acquisition system in plants.