The Hevea brasiliensis XIP aquaporin subfamily: Genomic, structural and functional characterizations with relevance to intensive latex harvesting

X-Intrinsic Proteins (XIP) were recently identified in a narrow range of plants as a full clade within the aquaporins. These channels reportedly facilitate the transport of a wide range of hydrophobic solutes. The functional roles of XIP in planta remain poorly identified. In this study, we found three XIP genes (HbXIP1;1, HbXIP2;1 and HbXIP3;1) in the Hevea brasiliensis genome. Comprehensive bioinformatics, biochemical and structural analyses were used to acquire a better understanding of this AQP subfamily. Phylogenetic analysis revealed that HbXIPs clustered into two major groups, each distributed in a specific lineage of the order Malpighiales. Tissue-specific expression profiles showed that only HbXIP2;1 was expressed in all the vegetative tissues tested (leaves, stem, bark, xylem and latex), suggesting that HbXIP2;1 could take part in a wide range of cellular processes. This is particularly relevant to the rubber-producing laticiferous system, where this isoform was found to be up-regulated during tapping and ethylene treatments. Furthermore, the XIP transcriptional pattern is significantly correlated to latex production level. Structural comparison with SoPIP2;1 from Spinacia oleracea species provides new insights into the possible role of structural checkpoints by which HbXIP2;1 ensures glycerol transfer across the membrane. From these results, we discuss the physiological involvement of glycerol and HbXIP2;1 in water homeostasis and carbon stream of challenged laticifers. The characterization of HbXIP2;1 during rubber tree tapping lends new insights into molecular and physiological response processes of laticifer metabolism in the context of latex exploitation.

Bibliographic Details

Main Authors:	Lopez, David, Ben Amira, Maroua, Brown, Daniel, Muries, Beatriz, Brunel-Michac, Nicole, Bourgerie, Sylvain, Porcheron, Benoit, Lemoine, Remi, Chrestin, Hervé, Mollison, Ewan, Di Cola, Alessandra, Frigerio, Lorenzo, Julien, Jean-Louis, Gousset-Dupont, Aurélie, Fumanal, Boris, Label, Philippe, Pujade-Renaud, Valérie, Auguin, Daniel, Venisse, Jean-Stéphane
Format:	article biblioteca
Language:	eng
Subjects:	F30 - Génétique et amélioration des plantes, F62 - Physiologie végétale - Croissance et développement, Hevea brasiliensis, latex, relation plante eau, génome, homéostasie, glycérol, phylogénie, saignée, http://aims.fao.org/aos/agrovoc/c_3589, http://aims.fao.org/aos/agrovoc/c_4214, http://aims.fao.org/aos/agrovoc/c_16147, http://aims.fao.org/aos/agrovoc/c_3224, http://aims.fao.org/aos/agrovoc/c_33930, http://aims.fao.org/aos/agrovoc/c_3298, http://aims.fao.org/aos/agrovoc/c_13325, http://aims.fao.org/aos/agrovoc/c_7611, http://aims.fao.org/aos/agrovoc/c_4027,
Online Access:	http://agritrop.cirad.fr/590820/ http://agritrop.cirad.fr/590820/1/Lopez%202016.pdf
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