根域限制对葡萄根中IAA含量及其代谢相关基因表达的影响

以1年生“玫瑰香”葡萄为试验材料,进行根域限制栽培处理,以传统地栽为对照,研究根域限制对葡萄根系构型、细胞结构、IAA含量及其代谢和根系生长发育相关基因表达丰度的影响,以探讨根域限制栽培影响葡萄根系构型变化的内在机制。结果表明:(1)根域限制处理后,葡萄根系构型发生显著变化,主要表现在根尖处出现大量集群根、不定根持续发生、根系出现螺旋卷曲;根系细胞排列更加疏松,幼根根尖的根冠区更厚,细胞更大、更长;毛细根的内皮层细胞加厚,中柱鞘和皮层细胞更大。(2)根域限制处理显著降低了葡萄根中IAA的含量;在葡萄定植后40、100和205 d时,根系IAA合成关键基因VvYUC6和VvYUC8的表达量变化趋势与IAA含量变化趋势一致,同时根域限制处理诱导IAA合成相关基因VvTAR2、VvYUC2和VvYUC4的表达水平在大部分采样时期显著上调;在定植后70、85、130和205 d时,根域限制导致VvAUX1、VvLAX1等8个IAA运输相关基因的表达水平显著上调,这与根域限制下根系大量发生的时期相吻合。(3)根域限制条件下,葡萄细胞周期调控相关基因VvcycA1、VvcycB1、VvcycD3和Vvcdc2在8月中旬到11月初呈上调表达趋势。研究表明,根域限制下葡萄根系构型、细胞结构以及内源IAA均发生显著变化;根域限制可能通过改变根系中生长素合成和极性运输相关基因的表达丰度,从而影响根系中生长素的合成和运输,进而改变葡萄的根系构型以适应根域限制的栽培环境。

Effect of Root Restriction on IAA Content and Metabolism related Gene Expression in Roots of Vitis vinifera

In this study, we selected the annual grapevine cv. Muscat Hamburg as the research material to explore the influence of root restriction on the growth and development of grape root system. By comparing with the traditional cultivation, we can understand the changes in grape root cell structure, IAA content and its metabolism and the expression of genes related to root growth and development after root restriction, thus explore the internal mechanism of root restriction cultivation affecting the changes of grape root system architecture. The results showed that: (1) after root restriction treatment, the architecture of grape root system changed significantly, which was mainly manifested in the appearance of a large number of clustered roots at the root tip, continuous adventitious roots, and the appearance of spiraling roots. In addition, the arrangement of root cells became looser, the root cap area of the young root tip was thicker, and the cells were larger and longer after root restriction. So, endothelial cells of the capillary roots were thickened, and the pericytes and cortical cells were larger. (2) Root restriction can significantly inhibit the content of IAA in grape roots. At 40, 100 and 205 d after planting, the changes in IAA content were consistent with the expression of key synthetic genes VvYUC6 and VvYUC8. Root restriction treatment induced the expression levels of IAA synthesis related genes VvTAR2, VvYUC2 and VvYUC4 to significantly up regulated during most sampling periods. At 70, 85, 130 and 205 d after planting, root restriction resulted in a significant up regulation of the expression levels of 8 genes related to IAA transport, such as VvAUX1 and VvLAX1, which coincided with the period when a high incidence of root system under root restriction. (3) Under root restriction, the expression of VvcycA1, VvcycB1, VvcycD3 and Vvcdc2 related to cell cycle regulation were up regulated from mid August to early November. Our studies have shown that root restriction leads to changes in the configuration and cell structure of the grapevine roots, and the IAA content also changes significantly. In addition, the induction of auxin synthesis and polar transport related gene expression abundance changes, thereby affecting the synthesis and transport of auxin in the root system, thus adapting grapes to the root restriction cultivation environment.