Soluble invertase expression is an early target of drought stress during the critical, abortion-sensitive phase of young ovary development in maize
Soluble invertase expression is an early target of drought stress during the critical, abortion-sensitive phase of young ovary development in maize
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DOI：
10.1104/pp.005637
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发表时间：
2002-10-01
期刊：
影响因子：
7.4
通讯作者：
Koch, KE
中科院分区：
文献类型：
--
作者：
Andersen, MN;Asch, F;Koch, KE
为了区分它们在早期籽粒发育和胁迫中的作用，分析了可溶性（lvr 2）和不溶性（Incw 2）酸转化酶在玉米（Zea mays）幼子房中从授粉前6 d（-6 d）到授粉后7 d（+7 d）以及响应干旱胁迫处理的扰动的表达。Ivr 2可溶性转化酶mRNA在整个授粉前和授粉后早期发育过程中比Incw 2 mRNA更丰富（在+3 d时达到峰值）。相反，Incw 2 mRNA仅在授粉后增加。Ivr 2可溶性转化酶的干旱抑制也先于Incw 2的变化，可溶性活性在授粉前（-4 d）响应。Ivr 2和Incw 2 mRNA的不同配置文件与各自的酶活性，并表示这些转化酶在卵巢发育和压力的单独作用。此外，干旱引起的子房己糖/蔗糖比的下降和发育变化与可溶性转化酶的活性有关，而与不溶性转化酶的活性无关。卵巢脱落酸水平仅在-6 d时因严重干旱而增加，并且似乎不直接影响Ivr 2表达。原位分析表明，本地化的活性和Ivr 2 mRNA的可溶性转化酶在韧皮部卸载和扩大母体组织（最大的终端维管区和附近的细胞果皮，花梗，和基础珠心）的网站。这种早期模式的母亲转化酶本地化是明显不同的特点协会不溶性转化酶与基础胚乳后来在发展。这种定位，在内源性己糖的蔗糖环境中的转变，和不同的时间可溶性和不溶性转化酶的表达在发展和压力共同表明的关键作用和关键敏感性的Ivr 2可溶性转化酶基因在早期，流产敏感的发展阶段。
To distinguish their roles in early kernel development and stress, expression of soluble (lvr2) and insoluble (Incw2) acid invertases was analyzed in young ovaries of maize (Zea mays) from 6 d before (-6 d) to 7 d after pollination (+7 d) and in response to perturbation by drought stress treatments. The Ivr2 soluble invertase mRNA was more abundant than the Incw2 mRNA throughout pre- and early post-pollination development (peaking at +3 d). In contrast, Incw2 mRNAs increased only after pollination. Drought repression of the Ivr2 soluble invertase also preceded changes in Incw2, with soluble activity responding before pollination (-4 d). Distinct profiles of Ivr2 and Incw2 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 hexose to sucrose 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 Ivr2 expression. In situ analysis showed localized activity and Ivr2 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 hexose to sucrose 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 Ivr2 soluble invertase gene during the early, abortion-susceptible phase of development.