Aquaporins, involved in the main water transport pathway across plasma
membranes in root and leaf tissues, are proposed to have a major role in
growth of plants due to their influence on root water uptake and leaf gas
exchange. Currently, a team of researchers from Zhejiang University in China
has overexpressed the soybean aquaporin GmPIP1;6 to evaluate its function
in growth regulation and salt tolerance in soybean.

GmPIP1;6 was found to be highly expressed in roots as well as reproductive
tissues. Treatment with 100 mM NaCl resulted in reduced expression
initially. However, after 3 days, its expression was increased in root and
leaves. The effects of overexpression of GmPIP1;6 in soybean was examined
under normal and salt stress conditions.

Growth was enhanced in the GmPIP1;6-overexpressing lines relative to
wildtypes under salt stress conditions. GmPIP1;6-overexpressing plants
maintained its root hydraulic conductance (Lo) under saline conditions
compared to wildtypes with decreased Lo. Transgenic lines grown in the field
had increased yield resulting mainly from increased seed size.

Results show that GmPIP1;6 could be a multifunctional aquaporin involved in
root water transport, photosynthesis and seed loading and will be a vital
gene for improving soybean.

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