Towards doubling fibre yield for cotton in the semiarid agricultural area by increasing tolerance to drought, heat and salinity simultaneously.

Nardana Esmaeili,Feiyu Tang,Paxton Payton,Jennifer Smith,Guoxin Shen,Yifan Cai,Glen Ritchie,Xunlu Zhu,Don Jones,Hong Zhang,Neelam Mishra,Eric Hequet

doi:10.1111/pbi.13476

Abstract

SummaryAbiotic stresses such as extreme temperatures, water‐deficit and salinity negatively affect plant growth and development, and cause significant yield losses. It was previously shown that co‐overexpression of the Arabidopsis vacuolar pyrophosphatase gene AVP1 and the rice SUMO E3 ligase gene OsSIZ1 in Arabidopsis significantly increased tolerance to multiple abiotic stresses and led to increased seed yield for plants grown under single or multiple abiotic stress conditions. It was hypothesized that there might be synergistic effects between AVP1 overexpression and OsSIZ1 overexpression, which could lead to substantially increased yields if these two genes are co‐overexpressed in real crops. To test this hypothesis, AVP1 and OsSIZ1 were co‐overexpressed in cotton, and the impact of OsSIZ1/AVP1 co‐overexpression on cotton's performance under normal growth and multiple stress conditions were analysed. It was found that OsSIZ1/AVP1 co‐overexpressing plants performed significantly better than AVP1‐overexpressing, OsSIZ1‐overexpressing and wild‐type cotton plants under single, as well as under multiple stress conditions in laboratory and field conditions. Two field studies showed that OsSIZ1/AVP1 co‐overexpressing plants produced 133% and 81% more fibre than wild‐type cotton in the dryland conditions of West Texas. This research illustrates that co‐overexpression of AVP1 and OsSIZ1 is a viable strategy for engineering abiotic stress‐tolerant crops and could substantially improve crop yields in low input or marginal environments, providing a solution for food security for countries in arid and semiarid regions of the world.

Highlights

Abiotic stresses refer to unfavourable growth conditions for plants that include high and low temperatures, water-deficit, salinity, nutrient starvation, and high light intensity
The Arabidopsis vacuolar H+-pyrophosphatase gene Arabidopsis vacuolar proton pyrophosphatase 1 (AVP1) and the rice SUMO E3 ligase gene OsSIZ1 were fused to Cauliflower mosaic virus 35S promoter and a maize ubiquitin promoter, respectively, with the nopaline synthase terminator sequence used in both expression cassettes
Our results indicate that cooverexpression of OsSIZ1 and AVP1 in cotton might activate different stress signalling pathways, leading to up-regulation of transcript levels of stress-related genes such as responsive to dehydrin 22 gene (RD22), HSFB2B, HSP70, HSP90, NCED3, RAB18, superoxide dismutase gene (SOD), CESA8, xyloglucan endotransglucosylase/hydrolase 6 (XTH6), resulting in significantly increased tolerance to environmental stresses in transgenic plants

Summary

Introduction

Abiotic stresses refer to unfavourable growth conditions for plants that include high and low temperatures, water-deficit, salinity, nutrient starvation, and high light intensity. Abiotic stresses are responsible for substantial yield losses annually for most crops. The upland cotton (Gossypium hirsutum L.) is an economically important crop for textile industry, providing 35% of the total fibre used worldwide (Abdelraheem et al, 2019). USA, China, Brazil and Pakistan produced most cotton fibres in the world (Abdelraheem et al, 2019). Except for Brazil, cotton production in the other four countries is mainly in regions where irrigation water is severely limited. In 2015, the United States Department of Agriculture predicted that a future decline in cotton production would likely occur because of drought stress. Cotton industry has been severely affected by drought and heat stresses, leading to a loss of fibre yield by 34% recently (Ullah et al, 2017)

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