Grasslands dominate the terrestrial landscape, and grasses have evolved complex and elegant strategies to overcome abiotic stresses. The C4 grasses are particularly stress tolerant and thrive in tropical and dry temperate ecosystems. Growing evidence suggests that the presence of C4 photosynthesis alone is insufficient to account for drought resilience in grasses, pointing to other adaptations as contributing to tolerance traits. The majority of grasses from the Chloridoideae subfamily are tolerant to drought, salt, and desiccation, making this subfamily a hub of resilience. Here, we discuss the evolutionary innovations that make C4 grasses so resilient, with a particular emphasis on grasses from the Chloridoideae (chloridoid) and Panicoideae (panicoid) subfamilies. We propose that a baseline level of resilience in chloridoid ancestors allowed them to colonize harsh habitats, and these environments drove selective pressure that enabled the repeated evolution of abiotic stress tolerance traits. Furthermore, we suggest that a lack of evolutionary access to stressful environments is partially responsible for the relatively poor stress resilience of major C4 crops compared to their wild relatives. We propose that chloridoid crops and the subfamily more broadly represent an untapped reservoir for improving resilience to drought and other abiotic stresses in cereals.

中文翻译：

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推动 C4 草和谷类非生物胁迫耐受性的进化创新

草原在陆地景观中占主导地位，草已经进化出复杂而优雅的策略来克服非生物胁迫。C4 草特别耐压，在热带和干燥的温带生态系统中茁壮成长。越来越多的证据表明，仅 C4 光合作用的存在不足以解释草的抗旱性，这表明其他适应性有助于耐受性状。Chloridoideae 亚科中的大多数草都耐受干旱、盐分和干燥，使这个亚科成为恢复力的中心。在这里，我们讨论了使 C4 草如此有弹性的进化创新，特别强调了来自 Chloridoideae (chloridoid) 和 Panicoideae (panicoid) 亚科的草。我们提出，氯化物祖先的基线复原力水平使它们能够在恶劣的栖息地定居，这些环境推动了选择性压力，使非生物胁迫耐受性状的重复进化成为可能。此外，我们认为，与野生近缘种相比，主要 C4 作物的抗逆力相对较差的部分原因是缺乏对压力环境的进化途径。我们建议氯化物作物及其亚科更广泛地代表了一个未开发的水库，用于提高谷物对干旱和其他非生物胁迫的抵御能力。我们认为，与野生近缘种相比，主要 C4 作物的抗逆力相对较差的部分原因是缺乏对压力环境的进化途径。我们建议氯化物作物及其亚科更广泛地代表了一个未开发的水库，用于提高谷物对干旱和其他非生物胁迫的抵御能力。我们认为，与野生近缘种相比，主要 C4 作物的抗逆力相对较差的部分原因是缺乏对压力环境的进化途径。我们建议氯化物作物及其亚科更广泛地代表了一个未开发的水库，用于提高谷物对干旱和其他非生物胁迫的抵御能力。