Aquaporin Gene Increases Fruit Size and Enhances Drought Tolerance in Tomato

Water deficit severely reduces apple growth and production and is detrimental to fruit quality and size. Thus, water-efficiency became the major target for apple breeding. Aquaporins control water transport across membranes and can regulate water flow by changing their amount and activity. The exploration of molecular mechanism of water efficiency will pave a way for breeding of drought tolerant apple trees.

Lin Wang of China Agricultural University, together with a team of researchers, focused on an apple (Malus domestica) drought inducible aquaporin gene, MdPIP1;3. The team expressed MdPIP1;3 gene in tomato. The transgenic tomatoes exhibited enhanced drought stress tolerance, indicating that water loss rate in transgenic leaves was slower than wild types.

The lengths and diameters of the transgenic tomato fruits increased faster that the wild types. Final fruit sizes and fresh weights of the transgenic tomatoes were also bigger and higher than wild types. In cell levels, fruit cell size from transgenic tomatoes was also larger.

Expressing MdPIP1;3 enhanced drought tolerance of transgenic tomatoes, partially by reducing water loss in leaves. The transgenic tomato fruits were also larger and heavier due to larger cells via more efficient water transport across membranes.

For more information on this study, read the article in BMC Plant Biology.