Clock-SAM · Transcriptional reprogramming of Clock at Shoot Apical Meristem in regulating plant organogenesis and growth.

Transcriptional reprogramming of Clock at Shoot Apical Meristem in regulating plant organogenesis and growth.

The increase on food consumption due to current global population growth places a higher demand to the agriculture sector to produce high-yielding crops with reduced inputs. Studies performed in Arabidopsis has demonstrated that circadian clock, which is an endogenous 24-hour time keeping machinery in plants, has a prominent effect on the physiology and development of plants. The circadian clock contributes to a vast developmental output such as flowering time, biomass allocation, photosynthesis, water uptake, temperature and stress responses. Plants with properly functioning clock match the day and night cycle to fix more carbon and grow faster. After germination, the shoot apical meristem produces leaves. The first leaves have a juvenile appearance and the leaves produced later gradually develop more adult characteristics as a result of robust meristem activity. Plant shoot apical meristems (SAM) are responsible for the production and regeneration of the different organs; factors that regulate both biomass and seed production. Despite the importance of stem cell function, the mechanisms controlling the timing of meristem activity in synchronization with the environment remain essentially unknown. The project provides novel information into the interactions between circadian clock and meristem function. It gives us great insights that the pace at which plants transition from juvenile to adult is tightly regulated by the transcriptional reprogramming controlled by the circadian clock at the shoot meristem. Our studies have shown that the shoot apex clocks are highly coupled or interconnected, as compared to clocks from other tissues. Consistently, clock mutant and over-expressing plants display alterations in SAM function manifested, for instance, in small organ sizes with a considerable reduction of cell numbers in the aerial organs. Clock miss-expression affects the pace of primordia appearance and the control of cell size and number during primordia initiation. Figure:A simplified model showing the importance of clock synchrony in plants through the SAM. Alteration of clock at SAM regulates various developmental processes throughout the life cycle of plants including early seedling, development, phenology and flowering.

Data: CORDIS, © European Union