石刁柏两性花与雄花的抗氧化酶活性及其相关基因可变剪接的差异分析

Differences of antioxidant enzyme activities and alternative splicing of related genes between hermaphroditic and male flower buds in asparagus

石刁柏(Asparagus officinalis),别名芦笋,其两性株是培育石刁柏全雄品种的重要资源材料。为探明引起石刁柏两性花与雄花之间性别差异的原因,首先测定了两性花与雄花性别分化前期、中期、后期三个时期花蕾的过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)的活性,同时采用转录组测序(RNA-seq)技术,分析了两性花与雄花三个不同发育时期花蕾中抗氧化酶基因的可变剪接及表达量的差异。结果发现,抗氧化酶活性与两性花、雄花的发育关系密切。在性别分化前期,两性花蕾中POD和SOD的活性均低于雄花蕾,CAT活性略高于雄花蕾,但在性别分化的中、后期,两性花蕾中POD和SOD的活性均高于雄花蕾,其中POD活性分别高出雄花蕾1.1和2.4倍,CAT活性略低于雄花蕾。通过RNA-seq及基因功能分类(GO)分析,表明其中有35个抗氧化活性相关基因只在两性花蕾中发生可变剪接,并且在石刁柏花器官性别分化前、中期,这35个抗氧化活性相关基因中分别有62.9%和65.7%的基因表达量高于雄花蕾。以上两方面的变化可能同时引起了石刁柏两性花蕾中抗氧化酶活性的升高。由此说明,抗氧化酶活性及相关基因的可变剪接与石刁柏两性花、雄花的发育紧密相关。

The hermaphroditic plant is an important resource material for breeding all-male varieties of asparagus (Asparagus officinalis).In order to find out the reasons for the formation of the hermaphroditic flowers and the degeneration of pistils in male flowers of asparagus,the activities of peroxidase (POD),catalase (CAT) and superoxide dismutase (SOD) were determined both in hermaphroditic and male flower buds at three representative stages (before,during and after the sex determinations).Meanwhile,transcriptome of male and female flower buds were obtained by RNA-seq and alternative splicing and differential expressions of antioxidant enzyme- related genes in hermaphroditic and male flower buds at three developmental stages were analyzed.The results show that the activities of antioxidant enzymes are closely related to the pistil development both in hermaphroditic and male flower buds.At early stage,compared to male flower buds,the activities of POD and SOD were lower and CAT activity was slightly higher in hermaphroditic flower buds.However,in the middle and late stages,the activities of POD and SOD in hermaphroditic flower buds was higher than those in male flower buds,and the activity of POD in hermaphroditic flower buds was higher than that in male flower buds by 1.1 and 2.4 folds,respectively.The CAT activity in hermaphroditic flower buds was slightly lower than that in male flower buds.Moreover,it was shown that 35 antioxidant-related genes were alternatively spliced only in hermaphroditic flower buds by RNA-seq and gene ontology (GO) enrichment analysis.At the early and middle stages,62.9% and 65.7% genes of 35 antioxidant-related genes in hermaphroditic flower buds were higher than those in male flower buds,respectively.These changes may also lead to the increase of antioxidant enzyme activities in hermaphroditic flower buds.Therefore,the activities of antioxidant enzymes and their alternative splicing of related genes were closely related to the development of pistil in asparagus hermaphroditic and male flowers.