Ph.D. Program in Plant Molecular Biology

Friday seminar by Ms. Pratibha Gour

SR Lab/Friday/April 20, 2018/3.30 pm/ How plants form their sugar transport routes
Category: Research

How plants form their sugar transport routes

During experiments on transport tissues in plants, researchers from Heidelberg University identified factors of crucial importance for the formation of the plant tissue phloem. These factors differ from all previously known factors that trigger the specification of cells. These factors are the proteins SMXL3, SMXL4, and SMXL5. They act in the nuclei of cells that develop into phloem tissue, and from there alter the cells to specialize in transport. Within the SMXL gene family, specifically SMXL3/4/5 deficiency results in strong defects in phloem formation, altered sugar accumulation, and seedling lethality. By comparing protein stabilities, they show that SMXL3/4/5 proteins function differently to canonical strigolactone and karrikin signaling mediators, although being functionally interchangeable with those under low strigolactone/karrikin signaling conditions. The researchers explain that the factors are similar to others involved in hormonal signal transmission – but they do not react to these hormones. This unresponsiveness is crucial for building robust phloem tissue and therefore for the growth of the plant in general. These observations reveal a fundamental mechanism of phloem formation and indicate that diversity of SMXL protein functions is essential for a steady fuelling of plant meristems.