Plant Root Lignification Status Effects Root Microbiome Profiles

Plant engineer their root associated microbial communities through root exudates. The overall plant vigor depends upon the efficiency of root microbiome that provides the plant with necessary nutrients, growth supplements and defense componuds. However, during maturation plant root components especially the endodermis and associated Casparian Strips (CS) undergo several differentiation processes implying sequential lignification and suberization thereby offering differential absorbing and protective functions. Early CS polymer is made from monolignol (lignin monomers) and is composed of lignin, functionally sufficient to block extracellular diffusion. However, by contrast, suberin is formed much later as a secondary wall and interestingly stress hormones abscisic acid and ethylene mediate its ability to responds to a variety of abiotic stresses for maintaining nutrient homeostasis. In addition to that, here we propose that differential levels of lignin and suberin during early root differentiation might be responsible for the early establishment of microbes inside and around the roots and hence shape the overall root microbiome in plants.