Molecular insights into the plasma membrane intrinsic proteins roles for abiotic stress and metalloids tolerance and transport in plants

Aquaporins are channel proteins reported to play multiple functions in plants ranging from water, solutes, metalloids (arsenic, boron, silicon) transport, and tolerance to abiotic stresses including drought, salinity and cold. Based on their localization and sequence similarities, aquaporins have been classified into seven major subfamilies: plasma membrane intrinsic proteins (PIPs), nodulin 26-like intrinsic proteins, tonoplast intrinsic proteins, small basic intrinsic proteins, GlpF-like intrinsic protein, hybrid intrinsic proteins and the uncategorized (X) intrinsic proteins. PIP subfamily is one of the biggest subfamilies of aquaporin superfamily and they are localized to plasma membrane. Members of PIPs are involved in water and small neutral solute transport and play an important role in maintaining water homeostasis under environmental stress and are known to provide tolerance to various abiotic stresses. Recently, members of PIP subfamily have been shown to be involved in the bidirectional transport of metalloids, arsenic and boron in plants. This review highlights the involvement of various PIP homologs in plant stress responses against a variety of environmental stresses and metalloid transport and tolerance. Molecular insights and biotechnological approaches for developing climate resilient crops by modulating PIPs will be discussed. © 2018, Indian Society for Plant Physiology.