Prof. Chuan-En Zhou’s group at School of Life Sciences, Shandong University published research in the top journal of Proceedings of the National Academy of Sciences of the United States of America (PNAS), entitled “ AGLF provides C-function in floral organ identity through transcriptional regulation of AGAMOUS in Medicago truncatula ”. Assistant researcher Yang Zhao is the first author; Prof. Chuan-En Zhou is the corresponding author. The key laboratory ofPlant Development and Environmental Adaptation Biologyand School of Life Sciences are the first corresponding institutions.

Based on genetic studies in Arabidopsis thaliana and Antirrhinum majus, the ABC model has been theorized to explain the mechanism underlying floral organ development. In general, sepals are controlled by Class A genes; petals are controlled by Class A genes and Class B genes; stamens are controlled by Class B genes and Class C genes; and carpels are controlled by Class C genes only. Medicago truncatula has been studied as the model legume species, which develops different floral architecture from Arabidopsis. The genome ofM.truncatula contains several canonical ABC genes, but their mutants showed slightly different phenotypes. In this work, a novel gene, AGAMOUS-LIKE FLOWER (AGLF), was identified from a forward genetic screen of Medicago mutants. The mutant showed homeotic transformation of floral organs, with stamen and carpel replaced by multiple petals and sepals. AGLF is a single copy gene, mutation of which displayed a similar phenotype as the well-studied Class C gene, AGAMOUS. This work represents a systematic research on floral organ development in Medicago truncatula and provides novel insights into breeding of other legume crops.

This work was supported by 973 Program Youth Project of the Ministry of Science and Technology of China, and the National Natural Science Foundation of China and of Shandong Province.