Scientists have made progress in the phenomenon of "bamboo flowering" and the evolution of FT genes encoded by flowering hormones

April 28, 2024 Source: Kunming Institute of Botany

The phenomenon of "bamboo flowering" refers to the biological phenomenon in which a plant undergoes years of nutritional growth before transitioning to reproductive growth, and after the last flowering and fruiting, the plant population dies. This phenomenon was first discovered in woody bamboo and has attracted widespread attention from biologists. In fact, the phenomenon of perennial one-time flowering exists in more than 20 families (genera) of angiosperms, including eudicotyledonous plants in the order Lamiaceae, family Acanthaceae, and genus Malaya. Due to the long nutritional growth cycle, research on the phenomenon of "bamboo flowering" mainly focuses on the description of morphology and growth habits, and its molecular genetic regulation mechanism lags behind plant groups with other flowering habits.

Hu Jinyong and Li Dehao from the Kunming Institute of Botany of the Chinese Academy of Sciences, together with Deng Yunfei's team from the South China Botanical Garden of the Chinese Academy of Sciences, based on the concept of "natural mutation", have constructed a high-quality full length transcriptional profile database and a multi tissue, multi developmental gene expression map of the perennial once flowering plant Hunan Malay and the perennial multi flowering plant Four Child Malay. It is found that photoperiod biological clock pathway genes such as FRS12, NFYA1, PRR5, etc. may be involved in regulating the flowering of four child Malay and maintaining the vegetative growth period of Hunan Malay. This research result echoes the team's previous discovery of flowering pathway variations in woody bamboo through comparative genetics.

To further elucidate the molecular mechanisms underlying the diversity of flowering habits in plants of the Malacca genus, the research team systematically compared and analyzed the evolutionary patterns of the key node gene FT (encoding flowering hormone) in the photoperiod biological clock pathway of plants in the Lamiaceae order. It was found that the FT branch expanded in multiple groups of angiosperms such as the order Fabales, the order Malvaceae, the order Sapinda, and the order Lamiaceae, forming two major branches, FT1 like and FT2 like, in the order Lamiaceae. Unlike the MFT2 like branch, which was preserved after replication in the ancestral taxa of angiosperms, the FT2 like branch first appeared in the family Scrophulariaceae, but there was dynamic expansion and/or loss in subsequent taxa. There is no collinearity between the two branches, and the origin mechanism is different. That is, the copy number variation within the FT1 like branch is mainly triggered by the cL-WGD event shared by the core labiiformes, accompanied by tandem duplication or random replication events; The expansion of FT2 like genes is mainly caused by random replication and is fixed, accompanied by tandem duplication or random replication events. Further analysis indicates that the expression patterns of FT1 like and FT2 like genes in different tissues of multiple species show differentiation after doubling. These results lay the foundation for further exploring the diversity of flowering habits in angiosperms, especially the molecular regulatory mechanisms of phenomena similar to bamboo flowering.

Recently, the related results were published in the Journal of Experimental Botany under the title of Evolution of the FLOWERING LOCUS T-like genes in angiosperms: a core Lamales specific differentiation. The research work was supported by the Chinese Academy of Sciences strategic leading science and technology project, the National Natural Science Foundation of China, etc.

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