【摘要】：野生二粒小麥是普通小麥A、B染色體組的供體祖先種,具有籽粒蛋白質含量高且籽粒微量元素含量高等特點。現(xiàn)代栽培小麥具有較高的產量,但品質亟待提高。NAM-B1基因在野生二粒小麥中普遍存在,在生育后期表達,一方面加速植株衰老,另一方面促進營養(yǎng)器官中的N、Fe、Zn等營養(yǎng)物質向發(fā)育中的籽粒轉運。然而在現(xiàn)代栽培小麥中,NAM-B1基因或是被刪除,或是由于在編碼區(qū)中第11個堿基位點發(fā)生T堿基插入,導致移碼突變而喪失功能。本實驗通過對野生二粒小麥D1和D97與普通小麥川農16雜交F10代進行NAM-B1基因克隆和表達量測定,籽粒收獲后測定籽粒蛋白質含量和鐵、鋅含量,探究NAM-B1基因導入川農16后的序列變異和表達情況及該基因對營養(yǎng)品質的影響。主要研究結果如下：D1和D97攜帶表達型NAM-B1基因,其序列相比功能型NAM-B1基因序列DQ869673只有一個堿基的同義突變；川農16沒有對應PCR擴增產物,說明該基因被刪除。27份雜交Flo代株系中12份材料克隆結果與川農16一致,系缺失型；12份材料克隆結果與D1和D97一致,系野生型;3份材料NAM-B1基因序列存在編碼區(qū)中第11個堿基位點發(fā)生T堿基插入而導致的移碼突變,系無功能的突變型。開花期NAM-B1基因表達量處于較低水平,范圍是actin基因表達量的1/22—1/6,且不同材料間差異不顯著；開花15天后表達量較高,范圍是actin基因表達量的1/4.5—1/1.5,不同材料間表達量存在極顯著差異。攜帶野生型NAM-B1基因的F10代材料平均籽粒蛋白質含量顯著高于不攜帶野生型NAM-B1基因的F10代材料。12份攜帶野生型NAM-B1基因的F1o代材料中有4份顯著高于親本川農16,而15份不攜帶野生型NAM-B1基因的F10代材料中只有1份顯著高于川農16。攜帶野生型NAM-B1基因的F1o代材料平均籽粒Fe含量顯著高于不攜帶野生型NAM-B1基因的F10代材料,同樣顯著高于親本川農16。而攜帶野生型NAM-B1基因的Flo代材料、不攜帶野生型NAM-B1基因的F10代材料以及川農16平均籽粒Zn含量差異不顯著。攜帶和不攜帶野生型NAM-B1基因的F10代材料平均千粒重差異不顯著,但是均顯著高于親本川農16,這很可能“歸功于”我們自F2代起不斷沿著高產育種方向進行選擇。因為高粒重的材料存在“稀釋”效應,所以單位質量籽粒中的營養(yǎng)物質含量只是相對含量,不能正確反映營養(yǎng)物質向籽粒轉運的能力。計算千粒重和籽粒營養(yǎng)物質含量的乘積得到的每千粒營養(yǎng)物質含量才是絕對含量。野生型NAM-B1基因在六倍體背景下提高籽粒蛋白質絕對含量和籽粒鐵絕對含量,但是對籽粒鋅絕對含量的作用效果沒有達到顯著性水平。相關分析結果顯示攜帶野生型NAM-B1基因的Fl0代材料各營養(yǎng)品質指標間相關性明顯強于不攜帶野生型NAM-B1基因的F10代材料。籽粒營養(yǎng)物質相對含量和千粒重全部表現(xiàn)為負相關,有些達到了顯著水平,相比之下,籽粒營養(yǎng)物質絕對含量和千粒重相關性較弱,對于攜帶野生型NAM-B1基因的F1o代材料還表現(xiàn)為正相關。因為籽粒營養(yǎng)物質絕對含量才真正反映向籽粒轉運營養(yǎng)物質的能力,所以我們認為在后代中選育粒大、千粒重高的株系并不會造成品質低下的問題,通過對NAM-B1基因的利用、配合田間選種,就很有希望培育出既高產又優(yōu)質的小麥新品種。此外,NAM-B1基因的表達量和各營養(yǎng)品質指標的相關分析還表明影響蛋白質和鐵、鋅含量的因素很復雜,除了NAM-B1基因之外很可能還有其它基因在調控這些生理生化過程。
[Abstract]:Wild two-grain wheat is the donor ancestor of wheat A and B chromosome group, and has the characteristics of high protein content and high content of trace elements in grains. The modern cultivated wheat has higher yield, but the quality needs to be improved. The NAM-B1 gene is ubiquitous in the wild two-grain wheat, which is expressed in late-growing stage. On the one hand, the plant senescence is accelerated, and on the other hand, nutrient substances such as N, Fe, Zn and the like in the vegetative organs are transferred to the grain in the development. However, in modern cultivation of wheat, the NAM-B1 gene is either deleted, or due to the insertion of a T-base at the 11th nucleotide site in the coding region, the shift mutation is lost and the function is lost. In this experiment, the cloning and expression of NAM-B1 gene were determined by crossing F10 generations of wild two wheat D1 and D97 and common wheat Chuangnong 16, and the content of protein and iron and zinc content were determined after grain harvest. To investigate the sequence variation and expression of NAM-B1 gene and the effect of the gene on nutritional quality. The main results are as follows: D1 and D97 carry the expression type NAM-B1 gene, the sequence of which is similar to that of the functional NAM-B1 gene sequence DQ869673, only one base has synonymous mutation; the Sichuan farmer 16 does not correspond to the PCR amplification product, The gene was deleted. 12 of the 27 hybrid Flo strains were consistent with the Chuangnong 16, and the results of 12 materials were consistent with D1 and D97, which were wild-type. 3 portions of the NAM-B1 gene sequence present a shift mutation resulting from the insertion of a T base at the 11th nucleotide site in the coding region, and is a non-functional mutant. The expression level of NAM-B1 gene in flowering stage was at a low level, the range was 1/ 22/ 1/ 6 of the expression of survivin gene, and the difference between different materials was not significant. The average grain protein content of F10 generation material carrying wild type NAM-B1 gene is significantly higher than that of F10 generation material carrying wild type NAM-B1 gene. Only 1 of the 10-generation materials which did not carry the wild-type NAM-B1 gene were significantly higher than that of the non-wild-type NAM-B1 gene. The average grain Fe content of F1o material carrying the wild-type NAM-B1 gene is significantly higher than that of the F10 generation material which does not carry the wild-type NAM-B1 gene, and is also significantly higher than that of the parent Sichuan farmer 16. However, the Fo material carrying the wild-type NAM-B1 gene does not carry the F10 generation material of the wild-type NAM-B1 gene and the average grain Zn content of the Sichuan farmer 16 is not significant. The average 1000-grain weight difference of the F10 generation materials carrying and without the wild-type NAM-B1 gene was not significant, but they were significantly higher than that of the parent Chuangnong 16, which was very likely to 鈥渙we to鈥，

本文編號：2312984