乙烯调节菌丝体生长,原基形成,采后蘑菇在白色纽扣蘑菇中成熟和衰老,双孢蘑菇.然而,蘑菇如何检测到乙烯仍然是未知的。在这项研究中,我们在蘑菇中发现了两种杂种组氨酸激酶,命名为AbETR1和AbETR2的结构域结构与植物乙烯受体相似。AbETR1和AbETR2的跨膜螺旋在酵母细胞中表达并显示出乙烯结合活性。AbETR1和AbETR2表达下调的蘑菇菌株对乙烯抑制菌丝体生长的敏感性降低,乙烯调节自己的合成,采后蘑菇成熟,以及衰老和成熟相关基因的表达。因此,预期AbETR1和AbETR2是生物功能性乙烯受体,并且表现出与植物受体不同的作用模式。这里,我们填补了有关高级真菌乙烯受体的知识空白,发现乙烯受体的一种新的作用方式,确认乙烯是一种新的真菌激素,并为防止采后纽扣蘑菇的成熟和衰老提供了便利的方法。重要性乙烯调节细菌的多种生理活动,蓝藻,真菌,和植物,但是如何通过真菌感知乙烯仍然是未知的。在这项研究中,我们在担子菌真菌双孢蘑菇中鉴定了两种具有生物学功能的乙烯受体,填补了真菌乙烯受体缺陷的空白。此外,我们发现乙烯受体表达的减少有助于阻止采后纽扣蘑菇的成熟和衰老,表明两种真菌乙烯受体正调节乙烯反应,与植物中的情况相反。
Ethylene regulates mycelial growth, primordium formation, and postharvest mushroom maturation and senescence in the white button mushroom, Agaricus bisporus. However, it remains unknown how ethylene is detected by the mushroom. In this study, we found that two hybrid histidine kinases in the mushroom, designated AbETR1 and AbETR2, showed domain structures similar to those of plant ethylene receptors. The transmembrane helices of AbETR1 and AbETR2 were expressed in yeast cells and showed ethylene-binding activities. Mushroom strains with downregulated expressions of AbETR1 and AbETR2 showed reduced sensitivity to the ethylene inhibition of mycelial growth, ethylene regulation of their own synthesis, postharvest mushroom maturation, and senescence and expression of maturation- and senescence-related genes. Therefore, AbETR1 and AbETR2 are expected to be biologically functional ethylene receptors and exhibit a different mode of action from that of the receptors of plants. Here, we fill gaps in the knowledge pertaining to higher fungus ethylene receptors, discover a novel mode of action of ethylene receptors, confirm ethylene as a novel fungal hormone, and provide a facilitated approach for preventing the maturation and senescence of postharvest button mushrooms. IMPORTANCE Ethylene regulates diverse physiological activities in bacteria, cyanobacteria, fungi, and plants, but how to perceive ethylene by fungi only remains unknown. In this study, we identify two biologically functional ethylene receptors in the basidiomycete fungus Agaricus bisporus, which fills the gaps of deficient fungal ethylene receptors. Furthermore, we found that decreased expression of the ethylene receptors facilitates preventing the maturation and senescence of postharvest button mushrooms, indicating that the two fungal ethylene receptors positively regulate the ethylene response, in contrast to that in plants.