Co-expression of an ethylene receptor gene, ERS1, and ethylene signaling regulator gene, CTR1, in Delphinium during abscission of florets.
Co-expression of an ethylene receptor gene, ERS1, and ethylene signaling regulator gene, CTR1, in Delphinium during abscission of florets.
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DOI：
10.1016/j.plaphy.2004.07.006
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发表时间：
2004-09
期刊：
影响因子：
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通讯作者：
S. Kuroda;Yukio Hirose;M. Shiraishi;E. Davies;S. Abe
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文献类型：
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作者：
S. Kuroda;Yukio Hirose;M. Shiraishi;E. Davies;S. Abe
我们正在试图确定乙烯诱导飞燕草切花小花脱落的机制，最近发现了一个乙烯受体基因ERS1，并研究了它对乙烯处理的反应。为了鉴定飞燕草乙烯反应网络的其他成分，我们使用乙烯信号调节基因（CTR1）的丝氨酸/苏氨酸激酶结构域的共识序列对cDNA末端进行了3 ‘和5 ’快速扩增（RACE）。全长cDNA （2754 nt）编码一个800个氨基酸的蛋白，包含预期的丝氨酸/苏氨酸激酶结构域、一致的atp结合位点和丝氨酸/苏氨酸激酶催化位点。该蛋白与拟南芥和番茄的CTR1具有相当高的总体同源性（bbb50 %），在催化位点具有70 - 75%的同源性。在外源乙烯的作用下，切花在6小时内编码CTR1和ERS1的mRNA数量增加了一倍以上。同样，在收获后的6天内，小花中ERS1转录物的数量增加了一倍，可能是对内源乙烯的反应，而CTR1 mRNA的数量在同一时期增加了约40%。然而，在硫代硫酸银（一种乙烯抑制剂）的存在下，这两种转录本的水平在前8天基本保持不变，然后下降到非常低的水平。对照植株的小花在6 d时几乎完全脱落，而sts处理植株的小花在20 d时还没有脱落，此时小花几乎死亡。这些数据与内源性乙烯引起这两种转录本（及其编码蛋白）积累的假设一致，从而加速了切花的脱落并缩短了切花的有效保质期。
We are trying to determine the mechanisms responsible for ethylene-induced floret abscission in cut flowers of Delphinium and recently identified an ethylene receptor gene, ERS1, and studied its response to ethylene treatment. In order to identify additional components of the ethylene response network in Delphinium, we performed 3′ and 5′ rapid amplification of cDNA ends (RACE) using the consensus sequence of the serine/threonine kinase domain of the ethylene signaling regulator gene (CTR1) involved in the constitutive triple response (CTR) to ethylene. The full-length cDNA (2754 nt) encoded a protein of 800 amino acids, which contained the expected serine/threonine kinase domain, the consensus ATP-binding site, and the serine/threonine kinase catalytic site. The protein had quite high (>50%) overall identity to CTR1 from Arabidopsis and tomato, and 70––75% identity in the catalytic site. The amount of mRNA encoding both CTR1 and ERS1 more than doubled within 6 h in cut florets incubated in the presence of exogenous ethylene. Similarly, the amount of ERS1 transcript doubled in florets within 6 d of harvesting, presumably in response to endogenous ethylene, while CTR1 mRNA increased to about 40% over the same period. However, in the presence of silver thiosulfate (STS), an ethylene inhibitor, the level of both transcripts remained essentially unchanged for the first 8 d before declining to very low levels. Florets on the control plants had almost completely abscised by 6 d, but the florets on STS-treated plants had not abscised by 20 d, by which time the flowers were almost dead. The data are consistent with the hypothesis that endogenous ethylene evokes the accumulation of both these transcripts (and their encoded proteins), thereby speeding up abscission and reducing the useful shelf life of the cut flowers.