Maize gene editing for less space but greater yield

Teosinte ligule allele narrows plant architecture and enhances high-density maize yields

Less space but greater maize yield

To meet increasing demands for food, modern agriculture works with increasingly dense plantings. Tian et al. identified a gene in teosinte, the wild ancestor of maize, and used it to alter maize such that the plant has a narrower architecture that nonetheless allows leaves access to sunlight (see the Perspective by Hake and Richardson). The yield advantage only becomes evident with the high-density plantings characteristic of modern agriculture, perhaps explaining why this gene was not brought into the fold during the previous millennia of maize domestication.

Abstract

Increased planting densities have boosted maize yields. Upright plant architecture facilitates dense planting. Here, we cloned UPA1 (Upright Plant Architecture1) and UPA2, two quantitative trait loci conferring upright plant architecture. UPA2 is controlled by a two-base sequence polymorphism regulating the expression of a B3-domain transcription factor (ZmRAVL1) located 9.5 kilobases downstream. UPA2 exhibits differential binding by DRL1 (DROOPING LEAF1), and DRL1 physically interacts with LG1 (LIGULELESS1) and represses LG1 activation of ZmRAVL1. ZmRAVL1 regulates brd1 (brassinosteroid C-6 oxidase1), which underlies UPA1, altering endogenous brassinosteroid content and leaf angle. The UPA2 allele that reduces leaf angle originated from teosinte, the wild ancestor of maize, and has been lost during maize domestication. Introgressing the wild UPA2 allele into modern hybrids and editing ZmRAVL1 enhance high-density maize yields.

Jinge Tian, Chenglong Wang, Jinliang Xia, Lishuan Wu, Guanghui Xu, Weihao Wu, Dan Li, Wenchao Qin, Xu Han, Qiuyue Chen, Weiwei Jin, Feng TianScience 16 Aug 2019:Vol. 365, Issue 6454, pp. 658-664 DOI: 10.1126/science.aax5482