• The Triticum aestivum (wheat) genome encodes three isoforms of Rubisco activase (Rca) differing in thermostability, which could be exploited to improve the resilience of this crop to global warming. We hypothesized that elevated temperatures would cause an increase in the relative abundance of heat‐stable Rca1β.
• Wheat plants were grown at 25° C : 18°C (day : night) and exposed to heat stress (38° C : 22°C) for up to 5 d at pre‐anthesis. Carbon (C) assimilation, Rubisco activity, CA1Pase activity, transcripts of Rca1β, Rca2β, and Rca2α, and the quantities of the corresponding protein products were measured during and after heat stress.
• The transcript of Rca1β increased 40‐fold in 4 h at elevated temperatures and returned to the original level after 4 h upon return of plants to control temperatures. Rca1β comprised up to 2% of the total Rca protein in unstressed leaves but increased three‐fold in leaves exposed to elevated temperatures for 5 d and remained high at 4 h after heat stress.
• These results show that elevated temperatures cause rapid changes in Rca gene expression and adaptive changes in Rca isoform abundance. The improved understanding of the regulation of C assimilation under heat stress will inform efforts to improve wheat productivity and climate resilience.

中文翻译：

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热诱导的小麦Rubisco活化酶同工型丰度变化。

• 在小麦（小麦）基因组编码活化酶（RCA）的热稳定性不同，这可能被利用来提高本榨季全球变暖的弹性三种亚型。我们假设高温会导致热稳定Rca1β的相对丰度增加。
• 小麦植株在25°C：18°C（白天：夜晚）下生长，并在开花前暴露于热胁迫（38°C：22°C）下长达5 d。在热应激期间和之后，测量碳（C）同化，Rubisco活性，CA1Pase活性，Rca1β，Rca2β和Rca2α的转录本以及相应蛋白质产物的量。
• 在高温下，Rca1β的转录本在4小时内增加了40倍，而在植物恢复控制温度后4小时后，Rca1β的转录本又恢复了原始水平。在未受胁迫的叶片中，Rca1β占总Rca蛋白的2％，但是在暴露于高温5 d的叶片中，Rca1β的含量增加了三倍，并在热胁迫后4 h保持高水平。
• 这些结果表明，升高的温度引起Rca基因表达的快速变化和Rca同工型丰度的适应性变化。对热胁迫下碳同化规律的进一步了解将有助于提高小麦的生产力和气候适应力。