Abstract
We are developing a molecular breeding method for improving fruit quality by salt stress signaling using tomato cultivar Micro-Tom. Recently, it have been reported that salinity, droughth and ABA stimulate plant specific protein kinases, SNF1-related kinases (SnRKs). Plant SnRK family was classified to three subgroups; 1) SnRK1 regulating nutrient metabolisms, 2) SnRK2 involving tolerance against salinity and drough, 3) SnRK3/CIPK binding to calcineurin B-like molecules (CBL). We focused on SnRK2s and CIPKs, as candidates regulating sugar metabolism of tomato under salt stress. Thus, we started functional analysis of tomato SnRK2s and CIPKs by utilizing tomato EST data-base (MiBASE). Proein levels of a tomato SnRK2 homolog, SlSnRK2C, appeared to increase specifically during young fruits while there was no difference in mRNA leveles of SlSnRK2C among several organs of tomato. Involvement of the fruit-specifc SnRKs on regulation of sugar metabolisms in tomato fruit under salt stress will be discussed.
