番茄Dicer-like蛋白基因家族生物信息学与表达分析

Bioinformatic and Expression Analysis of Tomato Dicer-like Protein Gene Family

Dicer-like蛋白(DCLs)是RNA沉默机制中的重要参与者,通过miRNA进行基因调控和植物的抗病毒保护,并且还与其他生物和非生物胁迫有关。研究番茄中DCLs的蛋白质基本功能以及SlDCLs对环境的响应,可以为DCLs参与抗逆途径及其在逆境中的作用提供理论依据。为深入了解番茄中RNase Ⅲ核酸内切酶Dicer-like蛋白基因家族的特征,利用生物信息学的方法对番茄DCL蛋白基因家族成员进行染色体定位,分析蛋白质基本理化性质、系统发育进化、启动子顺式作用元件、蛋白质结构域等。并通过qRT-PCR方法检测基因在组织中的表达模式和对激素、低温、盐、干旱等胁迫的响应。结果表明:番茄DCL基因有7个,分为4个家族;主要蛋白结构域有5个,启动子区域有响应各类激素、光信号、干旱等逆境的顺式作用元件,包括SlDCL1启动子区域的响应低温作用元件,SlDCL2a的SA、ABA响应元件,SlDCL2b的光响应元件,SlDCL2c的ABA,Me-JA响应元件,SlDCL2d的赤霉素响应元件,SlDCL3的Me-JA、SA响应元件,SlDCL4的干旱响应元件。结果表明:DCL家族基因在不同组织中具有不同的表达模式;激素、低温和渗透胁迫处理可以抑制或激活该家族成员的表达。SlDCL1直接响应低夜温,SlDCL2a对渗透胁迫响应明显;SlDCL2b的转录水平受到NACl的负调控;SlDCL2c受到低温以及ABA的正调控;SlDCL2d受NACl与PEG的负调控;PEG可以促进SlDCL3和SlDCL4的表达。

Dicer-like proteins(DCLs) are important players in the RNA silencing machinery for gene regulation and plant protection against viruses through miRNAs, and are also associated with other biotic and abiotic stresses. Studying the basic protein functions of DCLs in tomato and the response of SlDCLs to the environment can provide a theoretical basis for the involvement of DCLs in resistance pathways and their role in adversity. To gain insight into the characteristics of the Dicer-like protein gene family of RNase Ⅲ nucleic acid endonucleases in tomato, the chromosomal localization of the tomato DCL protein gene family members, basic physicochemical properties of the proteins, phylogenetic evolution, promoter cis-acting elements, and protein structural domains were analyzed using bioinformatics methods. The expression patterns of the genes in tissues and their responses to stresses such as hormones, low temperature, salt and drought were also examined by qRT-PCR. The results showed that there were seven tomato DCL genes, divided into four families;there were five major protein structural domains, with cis-acting elements in the promoter region in response to various hormones, light signals, drought and other adversities, including the low temperature response element in the promoter region of SlDCL1, the SA, ABA response element in SlDCL2a, the light response element in SlDCL2b, SlDCL2c ABA, Me-JA response element of SlDCL2c, gibberellin response element of SlDCL2d, Me-JA, SA response element of SlDCL3, and drought response element of SlDCL4. The results showed that the DCL family genes have different expression patterns in different tissues;hormone, low temperature and osmotic stress treatments can inhibit or activate the expression of this family member. SlDCL1 responded directly to low night temperature, SlDCL2a responded significantly to osmotic stress;the transcript level of SlDCL2b was negatively regulated by NaCl;SlDCL2c was positively regulated by low temperature as well as ABA;SlDCL2d was negatively regulated by NaCl and PEG;PEG could promote the expression of SlDCL3 and SlDCL4.