Recently, the research group of Dr. Hua Qin and Prof. RongfengHuang from Biotechnology Research Institute, Chinese Academy of Agricultural Scienceshas dissected themolecular mechanism of the coordination of ethylene and ROS in controlling rice coleoptile growth.The results are published on Plant Communications with the title of “OsEIL1 and OsEIL2, two master regulators of rice ethylene signaling, promote the expression of ROS scavenging genes to facilitate coleoptile elongation and seedling emergence from soil”.

The coleoptile is critical for crop establishment because its length determines the maximum depth at which seeds can be sown and its elongation guarantees fast seedling establishment in the field. Thus, coleoptile elongation is an important trait for seedling emergence in direct-seeding cultivation in rice, and dissecting the molecular mechanism of coleoptile growth will facilitate the generation of direct-seeding rice.

As an important belowground plant ground organ, the root system mediates water and nutrient uptake and provides mechanical support for shoot growth, therefore, root development strongly affects plant growth and productivity. Rice is an importantstaple food for more than half of the world population, identification of key regulators of root growth and development could accelerate the cultivation of new rice varieties with high yield and ensure food security.

Ethylene is an important gaseous plant hormone that plays an important role in response to soil conditions during seedling emergence.In the present study, we report that ROS acts as downstream signals of ethylene to inhibit coleoptile elongation and promote coleoptile apices expansion to delay the emergence of rice seedlings from soil, and the ethylene signaling transcription factor OsEIL1 and OsEIL2 directly activate the expression of ROS scavenging genes OsVTC1-3, OsPRX37, OsPRX81, OsPRX82, and OsPRX88 to attenuate ROS accumulation in the upper part of coleoptile. Our findings enrich the molecular mechanisms by which ethylene regulates coleoptile growth in rice, and provide guidance for breeders to cultivate rice varieties suitable for direct-seeding.

This work was funded by National Natural Science Foundation of China, and the Agricultural Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences.