Recently, researchers from Biotechnology Research Institute (BRI) of Chinese Academy of Agricultural Sciences (CAAS), in collaboration with South China Agricultural University (SCAU) etc. reported their research results in a paper entitled “Local auxin biosynthesis regulates brace root angle and lodging resistance in maize” publishing in the internationally reputed journal  New Phytologist .

Root lodging poses a major threat to maize production, resulting in reduced grain yield and quality, and increased harvest costs. Researchers now combined expressional, genetic, and cytological studies to demonstrate a role of ZmYUC2 and ZmYUC4 in regulating gravitropic response of the brace root and lodging resistance in maize. They show that both ZmYUC2 and ZmYUC4 are preferentially expressed in root tips with partially overlapping expression patterns, and the protein products of ZmYUC2 and ZmYUC4 are localized in the cytoplasm and endoplasmic reticulum, respectively. The Zmyuc4 single mutant and Zmyuc2/4 double mutant exhibit enlarged brace root angle compared with the wild-type plants, with larger brace root angle being observed in the Zmyuc2/4 double mutant. Consistently, the brace root tips of the Zmyuc4 single mutant and Zmyuc2/4 double mutant accumulate less auxin and are defective in proper reallocation of auxin in response to gravi-stimuli. Furthermore, they show that the Zmyuc4 single mutant and the Zmyuc2/4 double mutant display obviously enhanced root lodging resistance. These combined results demonstrate that ZmYUC2- and ZmYUC4-mediated local auxin biosynthesis is required for normal gravity response of the brace roots and provide effective targets for breeding root lodging resistant maize cultivars.

Doctoral student Zhigang Zheng (SCAU), Dr. Baobao Wang (BRI, CAAS), and master student Chuyun Zhuo (SCAU) are the co-first authors of this research paper. Professor Haiyang Wang (SCAU) is the corresponding author. This research is funded by the National Key Research and Development Program of China (2021YFF1000301 and 2020YFE0202300), National Natural Science Foundation of China (32272189) and Hainan Yazhou Bay Seed Lab (B21HJ8101).

More information can be found through the link: https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.18733

Figure 1.   Enhanced root lodging resistance in the  Zmyuc4  and  Zmyuc2/4  mutants.

By Wang Baobao(wangbaobao@caas.cn)