Zhang Chaohui, Huang Tao, Shen Chaohui, Wang Xiaoting, Qi Yuancheng, Shen Jinwen, Song Andong, Qiu Liyou, Ai Yuncan
State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, P.R. China.
Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Ministry of Agriculture, College of Life Sciences, Henan Agricultural University, Zhengzhou, P.R. China.
Int J Med Mushrooms. 2016;18(12):1131-1140. doi: 10.1615/IntJMedMushrooms.v18.i12.80.
Ethylene biosynthesis and function in Agaricus bisporus (the button mushroom) remain uncertain. The enzyme activities of 1-aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) were detectable in A. bisporus AS2796 and inhibited by α-aminooxyacetic acid and Co2+. We cloned and sequenced 2 ACS genes (Ab-ACS1 and Ab-ACS2) and 1 ACO gene (Ab-ACO) from the mushroom strain. Ab-ACS1 and Ab-ACS2 demonstrated low amino acid sequence similarity. Ab-ACO demonstrated an amino acid sequence completely identical to that of ACO1_AGABI from A. bisporus. Antisense ACO significantly reduced ACO gene expression level, ACO enzyme activity, and ethylene production in the mushroom transformants. The transformants grew faster than the wild-type strain in sterilized compost and normally formed primordia when cultivated in sterilized compost with the sterilized casing vermiculite, but the wild-type strain did not. Our results show that ethylene is synthesized in button mushrooms via the ACC pathway. Ethylene inhibited button mushroom mycelial growth and development.
双孢蘑菇（洋蘑菇）中乙烯的生物合成及功能仍不明确。在双孢蘑菇AS2796中可检测到1-氨基环丙烷-1-羧酸（ACC）合酶（ACS）和ACC氧化酶（ACO）的酶活性，且其活性受α-氨基氧乙酸和Co2+抑制。我们从该蘑菇菌株中克隆并测序了2个ACS基因（Ab-ACS1和Ab-ACS2）和1个ACO基因（Ab-ACO）。Ab-ACS1和Ab-ACS2的氨基酸序列相似性较低。Ab-ACO的氨基酸序列与双孢蘑菇的ACO1_AGABI完全相同。反义ACO显著降低了蘑菇转化体中ACO基因表达水平、ACO酶活性和乙烯产量。在灭菌堆肥中，转化体比野生型菌株生长得更快，并且当在含有灭菌覆盖蛭石的灭菌堆肥中培养时能正常形成原基，而野生型菌株则不能。我们的结果表明，双孢蘑菇通过ACC途径合成乙烯。乙烯抑制双孢蘑菇菌丝体的生长和发育。
