Biological complexity: controls of plant root absorption (Introduction)

by David Turell , Friday, September 04, 2020, 20:58 (1541 days ago) @ David Turell

Carefully and complexly controlled to allow absorption of water, minerals and nutrients:

https://www.cell.com/current-biology/fulltext/S0960-9822(20)31154-4?_returnURL=https%3A...

"Casparian strips (CSs) are cell wall modifications of vascular plants restricting extracellular free diffusion into and out of the vascular system [1]. This barrier plays a critical role in controlling the acquisition of nutrients and water necessary for normal plant development. CSs are formed by the precise deposition of a band of lignin approximately 2 μm wide and 150 nm thick spanning the apoplastic space between adjacent endodermal cells. Here, we identified a copper-containing protein, Uclacyanin1 (UCC1), that is sub-compartmentalized within the CS. UCC1 forms a central CS nanodomain in comparison with other CS-located proteins that are found to be mainly accumulated at the periphery of the CS. We found that loss-of-function of two uclacyanins (UCC1 and UCC2) reduces lignification specifically in this central CS nanodomain, revealing a nano-compartmentalized machinery for lignin polymerization. This loss of lignification leads to increased endodermal permeability and, consequently, to a loss of mineral nutrient homeostasis.

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"In conclusion, this study reveals the first loss-of-function phenotype for members of the plant-specific blue copper protein family of phytocyanins. Several studies suggested their implication in lignin polymerization, but this has never previously been shown. Our analysis indicates a role for the uclacyanins in the deposition of lignin in a newly discovered nanoscale domain within the CS. Further, the subcellular localization of UCC1, and the phenotype of the ucc(s) mutants, reveals a sub-compartmentalization of the machinery required for lignin polymerization at the CS."

Comment: A highly definitive study of proteins and gene controls of root absorption which is precisely controlled. Too complex for any process of origination except by design.