Regulation of conidiation in Botrytis cinerea involves the light-responsive transcriptional regulators BcLTF3 and BcREG1
Regulation of conidiation in Botrytis cinerea involves the light-responsive transcriptional regulators BcLTF3 and BcREG1
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DOI：
10.1007/s00294-017-0692-9
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发表时间：
2017-10-01
期刊：
影响因子：
2.5
通讯作者：
Schumacher, Julia
中科院分区：
文献类型：
--
作者：
Brandhoff, Beate;Simon, Adeline;Schumacher, Julia
灰葡萄孢是一种寄主范围广泛的植物病原真菌。由于其快速生长和无性孢子（分生孢子）繁殖，这增加了接种压力，真菌是农业不同领域的严重问题。分生孢子的形成是由光促进的，而作为存活结构的菌核的形成是在没有光的情况下发生的。基于这一观察，假定的转录因子（TF）的表达诱导曝光后已被认为是激活分生孢子和/或抑制菌核发育的候选人。先前的研究报道了六种光响应转录因子（LTF）的鉴定，其中两种已被证实是关键的发育调节因子：BcLTF 2是分生孢子形成的正调节因子，其表达受BcLTF 1的负调节。在这里，其余四个LTF的功能特性的报告。BcLTF 3具有双重功能，因为它通过在光和黑暗中抑制bcltf 2来抑制分生孢子梗发育，并且此外对于分生孢子发生是必需的。在bcltf 3缺失突变体中，分生孢子初始生长为菌丝，菌丝发育为次级分生孢子梗。相反，在这些实验中，BcLTF 4、BcLTF 5和BcLTF 6没有明显的功能。BcREG 1，以前报道的毒力和分生孢子形成所需的，已被重新确定为光响应的转录调控因子。对bcreg 1过表达菌株的研究表明，BcREG 1通过在光照下作为BcLTF 2诱导的分生孢子的阻遏物和在黑暗中作为BcLTF 2独立的分生孢子程序的激活物来不同地影响分生孢子。
Botrytis cinerea is a plant pathogenic fungus with a broad host range. Due to its rapid growth and reproduction by asexual spores (conidia), which increases the inoculum pressure, the fungus is a serious problem in different fields of agriculture. The formation of the conidia is promoted by light, whereas the formation of sclerotia as survival structures occurs in its absence. Based on this observation, putative transcription factors (TFs) whose expression is induced upon light exposure have been considered as candidates for activating conidiation and/or repressing sclerotial development. Previous studies reported on the identification of six light-responsive TFs (LTFs), and two of them have been confirmed as crucial developmental regulators: BcLTF2 is the positive regulator of conidiation, whose expression is negatively regulated by BcLTF1. Here, the functional characterization of the four remaining LTFs is reported. BcLTF3 has a dual function, as it represses conidiophore development by repressing bcltf2 in light and darkness, and is moreover essential for conidiogenesis. In bcltf3 deletion mutants conidium initials grow out to hyphae, which develop secondary conidiophores. In contrast, no obvious functions could be assigned to BcLTF4, BcLTF5 and BcLTF6 in these experiments. BcREG1, previously reported to be required for virulence and conidiogenesis, has been re-identified as light-responsive transcriptional regulator. Studies with bcreg1 overexpression strains indicated that BcREG1 differentially affects conidiation by acting as a repressor of BcLTF2-induced conidiation in the light and as an activator of a BcLTF2-independent conidiation program in the dark.