| Light that can be sensed and transmited by light receptors of plants is a signal molecule.The plant phototropism is a response to the direction of blue light.There has been some progress on the study of the phototropism in the previous studies.However,the mechanism remains unclear.There are few studies on the mechanism of higher plants phototropism.In this study,'Italian Riesling' field seedlings of wine grape variety(Vitis vinifera L.)were used as materials,with leaves and petioles which grown under natural conditions as control and which were illuminated under the condition of leaves abaxial toward upward as treatment.Endogenous hormone of leaves and petioles in grape were determined in the phototropic response of leaves and petioles for studied the relationship between its phototropism and endogenous hormones.The anatomical structures of leaves and petioles were studied to determine,which were changes in leaves and petioles in the phototropic response of leaves and petioles.High throughput RNA-technology was employed to study the pathway and screen candidate genes that were related to phototropic responsee of leaves and petioles in grape.In order to provide a basis for further studying the mechanism of grape phototropism.The main results are as follows:1.Along with the extension of the illuminating time,the leaf thickness,upper epidermis thickness,and lower epidermis thickness of the grape leaves which were from the abaxial side toward upward leaves that were fixed became thinner as the light hours increased.The thinnest L4 was 97.85 ?m,8.82 ?m,and 6.68 ?m,respectively.And the control was significantly larger than the treatment.The thickness of the palisade tissue increased first and then decreased,while the sponge tissue thickness was opposite.The inner diameter of the petiole catheter was increased with the increase of the light hours,of which P4 was the largest that was 43.29 ?m.2.Along with the illumination time increasing,the content of IAA in leaves and petioles increased first and then decreased,and L1 and P2 were the highest,which were 168.64ng·g-1 and 164.22ng·g-1 respectively.The content of GA in petiole decreased,and Pck was the highest and P5 was the lowest,which were 277.16ng·g-1 and 229.91ng·g-1 respectively.3.High throughput RNA-seq results showed: High quality reads up to 90.15-94.21% out of which 91.76-92.38% were mapped to exon regions,3.81-4.47% to intron regions,and 3.70-4.00% to intergenic regions.There were a total of 181 DEGs compared to the leaf controls and treatments,and 1810 DEGs compared to the petiole controls and treatments.4.KEGG pathway enrichment analysis showed that 181 DEGs in leaf control and treatment were significantly enriched in the flavonoid biosynthesis pathway and circadian rhythm pathway;1810 DEGs in the petiole control and treatment were significantly enriched to phytohormone signal transduction pathways and endoplasmic reticulum protein processing pathways.5.HY5 that is a positive regulator of light signal pathway was up-regulated expression in the Circadian rhythm pathway of plants.Plant hormone signal transduction pathways were annotated to 44 DEGs and involved hormone signal transduction pathways such as auxin,gibberellin,abscisic acid,ethylene,cytokinin,and brassinosteroid.PIF3 that is a negative regulator of light signal pathway down-regulated expression in the GA signaling pathway.qRT-PCR analysis showed that although the relative expression levels of the 20 DEGs were somewhat different from the RNA-seq,the gene expression patterns were similar.In summary,the phototropism of the petiole may be the result of the interaction of various hormones.The petiole may play a dominant role in the phototropism of the grape.The grape phototropism is a complicated process that may require the leaves and the petioles work together.The anatomical structure of the leaf and petiole changes in response to light,and the inner diameter of the petiole catheter increases during this process,suggesting that water may play a positive role. |
PDF Full Text Request