Wheat (Triticum aestivum L.) is a temperate cereal with an optimum temperature range of 15-22°C during the grain filling stage. Heat stress is one of the major environmental constraints for wheat production worldwide. Temperatures above 25°C during the grain filling stage significantly reduced wheat yield and quality. This reduction was reported due to the inactivation of the soluble starch synthase, a key heat-labile enzyme in starch transformation of wheat endosperm. To improve wheat productivity under heat stress, the rice soluble starch synthase I, under the control of either a constitutive promoter or an endosperm-specific promoter, was expressed in wheat and the transgenic lines were monitored for expression and the effects on yield-related traits. The results showed that the transgenic wheat events expressed rice soluble starch synthase I at a high level after four generations, and transgenic plants produced grains of greater weight during heat stress. Under heat stress conditions, the thousand kernel weight increased 21-34% in T2 and T3 transgenic plants compared to the non-transgenic control plants. In addition, the photosynthetic duration of transgenic wheat was longer than in non-transgenic controls. This study demonstrated that the engineering of a heat tolerant soluble starch synthase gene can be a potential strategy to improve wheat yield under heat stress conditions.

中文翻译：

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转基因小麦中水稻可溶性淀粉合酶基因的表达提高了热胁迫条件下的谷物产量。

小麦 (Triticum aestivum L.) 是一种温带谷物，灌浆期的最佳温度范围为 15-22°C。热应激是全球小麦生产的主要环境限制之一。灌浆期气温高于25℃会显着降低小麦产量和品质。据报道，这种减少是由于可溶性淀粉合酶失活所致，可溶性淀粉合酶是小麦胚乳淀粉转化中的关键热不稳定酶。为了提高热胁迫下的小麦产量，在组成型启动子或胚乳特异性启动子的控制下，水稻可溶性淀粉合酶 I 在小麦中表达，并监测转基因品系的表达及其对产量相关性状的影响。结果表明，转基因小麦事件在四代后以高水平表达水稻可溶性淀粉合酶I，并且转基因植物在热胁迫期间产生更重的籽粒。在热胁迫条件下，与非转基因对照植物相比，T2和T3转基因植物的千粒重增加了21-34%。此外，转基因小麦的光合持续时间比非转基因对照更长。这项研究表明，耐热可溶性淀粉合酶基因的工程化可以成为在热胁迫条件下提高小麦产量的潜在策略。