三倍体枇杷坐果期内源激素测定及Aux/IAA基因家族表达分析

Phytohormone Content Detection and Expression Analysis of the Aux/IAA Gene Family DuringFruitSet of Triploid Loquat

将三倍体枇杷坐果期材料分为子房和其他部分,测定其4种内源植物激素的含量,并对6个Aux/IAA基因家族的时空表达特点进行了初步分析.结果表明:对于IAA来说,GA3处理后子房内IAA质量分数明显高于其他部分,并在处理后第5 d和第7 d出现了2个高峰,推测其质量分数升高可能与外源GA3处理有关,高质量分数的IAA替代受精作用从而诱导枇杷坐果.荧光定量PCR分析发现,GA3处理后6个基因的表达量都具有变化,IAA6,IAA8,IAA10在子房中的表达量明显高于其他部分,IAA9在子房和其他部分的表达量相当,IAA11和IAA20在子房中的表达量低于其他部分.此外,在外源GA3处理前期,子房中IAA9的表达量与内源IAA质量分数变化趋势一致,推测内源IAA质量分数升高,诱导IAA9表达上调,从而诱导枇杷果实坐果.IAA8在GA3处理3 d后表达量开始升高,并显著高于对照组,推测其功能可能与IAA9相似.

In a study reported in this paper,thefruit set material of triploid loquatwas divided into two parts:ovary and other parts,and the contentsof four endogenous phytohormones were determined,and the temporal and spatial expression characteristics of six genes of the Aux/IAA family were analyzed.The results showed that the content of IAA in the ovary was significantly higher than that in other parts after exogenous GA 3 treatment,andtwo peaks were detected 5 and 7 days after the treatment.It wasspeculatedthatthe increase of IAA might be related to exogenous GA 3 treatment,and the high concentration of IAA replaced fertilization to initiate triploid loquat fruit set.Real-time PCR analysis showed that the expression of all the six genes changed after GA 3 treatment.The expression level of IAA6,IAA8 and IAA10 in ovary was significantly higher than in other parts,IAA9 expression level was similar in ovary and other parts,while IAA11 and IAA20 expressed less in the ovary than in other parts.In addition,at theearly stage of exogenous GA 3 treatment,the expression of IAA9 in the ovary was consistent with the change in endogenous IAA content.The increase in endogenous auxin content resulted in the up-regulationof IAA9 expression,thereby inducing the loquat fruit set.In the ovary,IAA8 expression started to increase 3 daysafter exogenous GA 3 treatmentand was significantly higher than that of the control,suggesting that thefunction of IAA8 was probablysimilar to that of IAA9.