State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Wenjing, China.
Maize Research Institute, Sichuan Agricultural University, Wenjing, China.
Plant Biotechnol J. 2022 Nov;20(11):2077-2088. doi: 10.1111/pbi.13889. Epub 2022 Jul 22.
Root architecture remodelling is critical for forage moisture in water-limited soil. DEEPER ROOTING 1 (DRO1) in Oryza, Arabidopsis, and Prunus has been reported to improve drought avoidance by promoting roots to grow downward and acquire water from deeper soil. In the present study, we found that ZmDRO1 responded more strongly to abscisic acid (ABA)/drought induction in Zea mays ssp. mexicana, an ancestral species of cultivated maize, than in B73. It was proposed that this is one of the reasons why Zea mays ssp. mexicana has a more noticeable change in the downward direction angle of the root and fewer biomass penalties under water-deficient conditions. Thus, a robust, synthetic ABA/drought-inducible promoter was used to control the expression of ZmDRO1 in Arabidopsis and cultivated maize for drought-resistant breeding. Interestingly, ABA-inducible ZmDRO1 promoted a larger downward root angle and improved grain yield by more than 40% under water-limited conditions. Collectively, these results revealed that different responses to ABA/drought induction of ZmDRO1 confer different drought avoidance abilities, and we demonstrated the application of ZmDRO1 via an ABA-inducible strategy to alter the root architecture of modern maize to improve drought adaptation in the field.
根构型的重塑对于水分受限土壤中的饲草料获取至关重要。在水稻、拟南芥和李属中，已报道 DEEPER ROOTING 1（DRO1）通过促进根系向下生长并从更深的土壤中获取水分来提高耐旱性。在本研究中，我们发现ZmDRO1 对玉米的祖先进化物种——墨西哥玉米亚种的脱落酸（ABA）/干旱诱导的反应比 B73 更为强烈。有人提出，这是墨西哥玉米亚种的根向下方向角变化更为明显且在缺水条件下生物量损失更少的原因之一。因此，使用一个稳健的、合成的 ABA/干旱诱导启动子来控制 ZmDRO1 在拟南芥和栽培玉米中的表达，用于耐旱性育种。有趣的是，ABA 诱导型 ZmDRO1 在水分受限条件下促进更大的向下根角度，使籽粒产量提高了 40%以上。总之，这些结果表明 ZmDRO1 对 ABA/干旱诱导的不同反应赋予了不同的耐旱能力，我们通过 ABA 诱导型策略展示了 ZmDRO1 的应用，以改变现代玉米的根构型，提高其在田间的耐旱性。
