授粉对蓝莓生产至关重要,为探究不同授粉强度下柱头的响应机制及其特性,以'蓝源(M7)'为研究对象,比较不同花龄下柱头可授性,并对花粉活力进行测定,然后对3种授粉强度处理下的蓝莓柱头进行转录组测序和分析.结果表明,随花龄的不断延长,'蓝源(M7)'柱头可授性表现为先升高后逐渐降低的趋势,在开花第2天可授性最强.3种授粉强度的花粉表现出不同的活力,随着授粉强度的增加,柱头内参与花粉管生长调节的钙依赖蛋白激酶17(Cpk17)和涉及肌醇含量的肌醇加氧酶(MIOX1)等基因的表达量显著提高.对差异表达基因的GO(gene ontology)富集分析发现,与碳水化合物代谢、肌醇加氧酶活性和细胞壁组织相关的功能基因被显著富集;KEGG(kyoto encyclopedia of genes and genomes)富集分析发现,与植物-病原体互作和肌醇膦酸代谢相关的通路被显著富集.由此推测,授粉强度的增加可能对柱头和花粉的识别过程产生影响,通过参与柱头和花粉间的信号转导、激素合成过程对花粉管的生长起促进作用,进而影响受精过程.以上结果为理解蓝莓柱头对不同授粉强度的响应机制提供了理论参考,为蓝莓的精确授粉提供科学依据.
Transcriptome Analysis of Stigma Response Mechanism of Blueberry with Different Pollination Intensity
Pollination is essential for blueberry production.In order to explore the stigma response mechanism and its characteristics under different pollination intensities,the stigma acceptability of'Bluesouth(M7)'was compared at different florescence ages,and the pollen viability was determined.Transcripome sequencing and analysis were performed on the stigma of blueberry under 3 pollination intensities.The results showed that,with the increasing of flowering age,stigma receptivity of'Bluesouth(M7)'showed a trend of increasing first and then decreasing gradually,with the strongest receptivity on the second day of flowering.Pollen from 3 different pollination intensities showed different vigor.Blueberry stigma transcriptome data analysis revealed that with the increase in pollination intensity,the expression levels of gene CPK17 and gene MIOX1 were significantly upregulated.The GO(gene ontology)enrichment analysis of the differentially expressed genes showed that the genes involved in carbohydrate metabolic process,inositol oxygenase activity and cell wall organization were significantly enriched.KEGG(kyoto encyclopedia of genes and genomes)enrichment analysis showed that the pathways related to plant-pathogen interaction and inositol phosphate metabolism were significantly enriched.It was inferred that the increase of pollination intensity might affect the germination and growth of pollen tube,and then affect the fertilization process.These findings suggested that increased pollination intensity might impact the process of stigma and pollen recognition,and facilitate pollen tube growth through involvement in signal transduction and hormone synthesis between stigma and pollen.Above results provided a theoretical reference for understanding the mechanism of stigma response to different pollination intensities of blueberry,and provided scientific basis for precise pollination of blueberry.