【摘要】：NBS-encoding基因家族包括NBS-only類型和NBS-LRR類型的基因,且NBS-LRR基因家族是植物中最大的抗病基因家族之一,在抵御病原體的侵染過程中起到重要的作用。對NBS-encoding基因家族的分析研究對植物抗病基因的鑒定和篩選具有重要的意義。板栗和獼猴桃是我國重要的經(jīng)濟(jì)果樹,都含有較高的營養(yǎng)價(jià)值,但是病害嚴(yán)重制約板栗和獼猴桃產(chǎn)業(yè)的發(fā)展。所以,對板栗和獼猴桃的抗病基因的研究對于優(yōu)化農(nóng)業(yè)生產(chǎn)顯得尤為重要。本研究利用生物信息學(xué)的方法,從基因鑒定、家族劃分、復(fù)制時(shí)間、復(fù)制方式、選擇壓和啟動子區(qū)域的順式調(diào)控元件分析等幾個(gè)方面,對板栗和獼猴桃的NBS-encoding基因進(jìn)行了分析。1、本研究中我們從板栗全基因組中鑒定出519個(gè)NBS-encoding基因,其中含有374個(gè)NBS-LRR基因,復(fù)制時(shí)間相對古老,且復(fù)制方式為物種內(nèi)特異性復(fù)制。我們計(jì)算了Ka/K 來判斷基因受到的選擇壓作用,結(jié)果表明:大部分家族受到純化選擇,也有小部分家族受到了正選擇壓力。以Ks = 0.4～0.5為界,越新近和越古老的基因受到越大的選擇壓力作用。另外,我們發(fā)現(xiàn)RPW8-NBS-encoding基因群體是獨(dú)立于non-TIR-NBS-encoding基因的群體,且位于進(jìn)化樹相對基部的位置。此外,NBS-encoding家族基因的啟動子區(qū)域含有很多與植物抗性防御相關(guān)的順式調(diào)控元件。2、我們利用同樣的方法,在獼猴桃基因組中共鑒定出96個(gè)NBS-encoding基因,其中含有74個(gè)NBS-LRR基因。Ks頻率分布顯示,該家族的復(fù)制時(shí)間是新近的,而且越新近的基因在進(jìn)化過程中受到越小的選擇壓作用。絕大多數(shù)的基因家族的Ka/Ks小于1,說明純化選擇起重要的作用;同時(shí),鑒定出6個(gè)基因家族中125個(gè)氨基酸位點(diǎn)受到正選擇作用。
[Abstract]:NBS-encoding gene family includes NBS-only type and NBS-LRR type gene, and NBS-LRR gene family is one of the largest resistance genes in plants, which plays an important role in resisting pathogen infection. The analysis of NBS-encoding gene family plays an important role in the identification and screening of plant disease resistance genes. Chinese chestnut and kiwifruit are important economic fruit trees in China, both of which contain high nutritional value, but the disease seriously restricts the development of Chinese chestnut and kiwifruit industry. Therefore, the study of resistance genes of Chinese chestnut and kiwifruit is particularly important for optimizing agricultural production. In this study, bioinformatics was used to analyze gene identification, family division, replication time, replication mode, selection of pressure and analysis of cis regulatory elements in promoter regions. The NBS-encoding genes of Chinese chestnut and kiwifruit were analyzed. 1. In this study, 519 NBS-encoding genes were identified from the whole genome of Chinese chestnut, including 374 NBS-LRR genes. And the way of replication is specific within species. We calculated Ka/K to determine the selection pressure of genes. The results showed that most families were selected for purification and a few families were under positive selection pressure. The more recent and the older the gene is, the greater the selection pressure is when the Ks = 0. 4 ~ 0. 5 is used as the boundary. In addition, we found that the RPW8-NBS-encoding gene population is independent of the non-TIR-NBS-encoding gene and is located at the base of the evolutionary tree. In addition, the promoter region of the NBS-encoding family gene contains many cis-regulatory elements related to plant resistance defense. 2. Using the same method, 96 NBS-encoding genes were identified in kiwifruit genome. The Ks frequency distribution showed that the replication time of the family was recent and the more recent genes were subjected to less selective pressure during evolution. The Ka/Ks of most gene families was less than 1, which indicated that purification selection played an important role, and 125 amino acid sites in 6 gene families were positively selected.
【學(xué)位授予單位】：南京農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：S664.2;S663.4

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相關(guān)期刊論文 前1條

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