Invertase inhibitor (INH) post-translationally regulates the activity of invertase, which hydrolyzes sucrose into glucose and fructose, and plays essential roles in plant growth and development. However, little is known about the role of INH in growth and responses to environmental challenges in sweetpotato. Here, we identified and characterized an INH-like gene (IbINH) from sweetpotato. IbINH belongs to the pectin methylesterase inhibitor super family. IbINH transcript was the most abundant in storage roots. IbINH mRNA levels were significantly up-regulated in response to drought, abscisic acid (ABA), salicyclic acid (SA) and jasmonic acid (JA) treatments. Overexpressing IbINH in sweetpotato (SI plants) led to the decrease of plant growth and the increase of drought tolerance, while down-regulation of IbINH (RI plants) by RNAi technology resulted in vigorous growth and drought sensitivity. Furthermore, sucrose was increased and hexoses was decreased in SI plants, but the opposite results were observed in RI plants. Moreover, higher levels of sugars were accumulated in SI plants in comparison to non-transgenic plants (NT plants) and RI plants during water deficit. In addition, ABA biosynthesis-involved and abiotic stress response-involved genes were prominently up-regulated in SI plants under drought stress. Taken together, these results indicate that IbINH mediates plant growth and drought stress tolerance in sweetpotato via induction of source-sink strength and ABA-regulated pathway.

中文翻译：

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IbINH积极调节甘薯的干旱胁迫耐受性。

转化酶抑制剂（INH）在翻译后调节转化酶的活性，该酶将蔗糖水解为葡萄糖和果糖，并在植物生长和发育中起重要作用。然而，人们对INH在甘薯的生长和对环境挑战的反应中所起的作用知之甚少。在这里，我们鉴定并鉴定了甘薯中的INH样基因（IbINH）。IbINH属于果胶甲基酯酶抑制剂超家族。IbINH转录本是储存根中最丰富的。IbINH mRNA水平在干旱，脱落酸（ABA），水杨酸（SA）和茉莉酸（JA）处理下明显上调。在甘薯（SI植物）中过分表达IbINH导致植物生长下降和耐旱性增加，RNAi技术对IbINH（RI植物）的下调导致了旺盛的生长和干旱敏感性。此外，SI植物中蔗糖增加而己糖减少，但是在RI植物中观察到相反的结果。此外，与非转基因植物（NT植物）和RI植物在缺水期间相比，SI植物中积累了更高水平的糖。此外，干旱胁迫下SI植物中与ABA生物合成有关的基因和与非生物胁迫响应有关的基因均显着上调。综上所述，这些结果表明，IbINH通过诱导源库强度和ABA调节途径介导甘薯的植物生长和干旱胁迫耐受性。但是在RI植物中观察到相反的结果。此外，与非转基因植物（NT植物）和RI植物在缺水期间相比，SI植物中积累了更高水平的糖。此外，干旱胁迫下SI植物中与ABA生物合成有关的基因和与非生物胁迫响应有关的基因均显着上调。综上所述，这些结果表明，IbINH通过诱导源库强度和ABA调节途径介导甘薯的植物生长和干旱胁迫耐受性。但是在RI植物中观察到相反的结果。此外，与非转基因植物（NT植物）和RI植物在缺水期间相比，SI植物中积累了更高水平的糖。此外，干旱胁迫下SI植物中与ABA生物合成有关的基因和与非生物胁迫响应有关的基因均显着上调。综上所述，这些结果表明，IbINH通过诱导源库强度和ABA调节途径介导甘薯的植物生长和干旱胁迫耐受性。在干旱胁迫下，SI植物中涉及ABA生物合成和涉及非生物胁迫反应的基因显着上调。综上所述，这些结果表明，IbINH通过诱导源库强度和ABA调节途径介导甘薯的植物生长和干旱胁迫耐受性。在干旱胁迫下，SI植物中涉及ABA生物合成和涉及非生物胁迫反应的基因显着上调。综上所述，这些结果表明，IbINH通过诱导源库强度和ABA调节途径介导甘薯的植物生长和干旱胁迫耐受性。