Soluble invertase expression is an early target of drought stress during the critical, abortion-sensitive phase of young ovary development in XXXX .

@entity69571 @entity2829 @entity12015 @entity969 @entity70990
To distinguish their roles in early kernel development and stress, expression of soluble ( @entity69571 ) and insoluble ( @entity70990 ) acid invertases was analyzed in young ovaries of @entity2829 ( @entity2829 ) from 6 d before (-6 d) to 7 d after pollination (+7 d) and in response to perturbation by drought stress treatments. The @entity69571 soluble invertase mRNA was more abundant than the @entity70990 mRNA throughout pre- and early post-pollination development (peaking at +3 d). In contrast, @entity70990 mRNAs increased only after pollination. Drought repression of the @entity69571 soluble invertase also preceded changes in @entity70990 , with soluble activity responding before pollination (-4 d). Distinct profiles of @entity69571 and @entity70990 mRNAs correlated with respective enzyme activities and indicated separate roles for these invertases during ovary development and stress. In addition, the drought-induced decrease and developmental changes of ovary @entity12015 to @entity969 ratio correlated with activity of soluble but not insoluble invertase. Ovary abscisic acid levels were increased by severe drought only at -6 d and did not appear to directly affect @entity69571 expression. In situ analysis showed localized activity and @entity69571 mRNA for soluble invertase at sites of phloem-unloading and expanding maternal tissues (greatest in terminal vascular zones and nearby cells of pericarp, pedicel, and basal nucellus). This early pattern of maternal invertase localization is clearly distinct from the well-characterized association of insoluble invertase with the basal endosperm later in development. This localization, the shifts in endogenous @entity12015 to @entity969 environment, and the distinct timing of soluble and insoluble invertase expression during development and stress collectively indicate a key role and critical sensitivity of the @entity69571 soluble invertase gene during the early, abortion-susceptible phase of development.
