Recently, researchers from Biotechnology Research Institute of Chinese Academy of Agricultural Sciences (CAAS), in collaboration with South China Agricultural University, have published their research results entitled “Characterization of Maize Phytochrome-Interacting Factors in Light Signaling and Photomorphogenesis” on Plant Physiology. This work reveals the molecular mechanism of Phytochrome-Interacting Factor (PIF) in regulating shade avoidance response in maize, which is of great significance to cultivate new varieties of high-density planting maize.

Increasing planting density is an effective means to increasing maize yields. However, high density planting will trigger shade avoidance syndrome (SAS), including increased plant and ear height, increased lodging and reduced yield. It has been well documented that PIFs, the key regulator of shade avoidance, play critical roles in SAS in a number of plant species. However, it is still unclear which and how PIF genes are involved in the process of phytochrome-mediated shade avoidance response in maize.

In this study, researchers found that the maize genome contains seven distinct PIF genes and all the seven PIF proteins could interact with ZmphyB. Moreover, the Zmpif knockout mutants generated via CRISPR/Cas9 technology all showed severely suppressed mesocotyl elongation in dark-grown seedlings, and were less responsive to simulated shade treatment in plant height elongation, which could inhibit the rapid growth of elongation and ultimately achieve the goal of reducing plant height.

Postdoctoral fellow Guangxia Wu, from Innovation Team of Maize Functional Genomics, is the first author of this research and the correspondent author is Professor Haiyang Wang, from South China Agricultural University. This research was funded by National Natural Science Foundation of China (grant no. 31601319) and Beijing Natural Science Foundation (grant no. 6174050).

by: Guangxia Wu (wuguangxia@caas.cn)