Gibberellin-mediated Regulation Of Mycorrhizal Symbiosis In Banana

Arbuscular mycorrhizal fungi increase the absorption of phosphorus by bananas,increase the synthesis of carbohydrates,and promote the growth of bananas.Gibberellin plays an important role in the mycorrhiza process.Changes the hormones when affect the progress of mycorrhiza.The mechanism of gibberellin mediated by banana mycorrhiza remains to be further studied.This experiment designed four different treatments,inoculation of arbuscular mycorrhizal fungi?Gi?;exogenous application of gibberellic acid?GA₃?;exogenous application of gibberellin?Gi+GA₃?after inoculation of arbuscular mycorrhizal fungi?CK?.After 60 days of planting,the physiological indexes were determined.The content of endogenous hormones in Brazilian banana was detected by ultra performance liquid chromatography.The effects of gibberellin on banana mycorrhiza were analyzed by transcriptome sequencing technology.The main results are as follows:?1?Compared with CK,in the treatment group,the upper part of Brazilian banana land was fresh and heavy,and the plant height and stem diameter increased significantly.In the Gi+GA₃ treatment,the maximum root length of the banana was14.75 cm,the most significant effect.Compared with GA₃ treatment,Gi+GA₃treatment showed a significant increase in total banana plant height,plant height and maximum root length,which increased by 73%,17%,and 163%,respectively.After inoculation with Gi,the mycorrhizal infection rate was 25%.After exogenous application of gibberellin,the mycorrhizal infection rate was reduced to 16%.?2?Compared with GA₃ treatment,Gi+GA₃ treatment showed a significant increase in banana peroxidase and phenylalanine ammonia-lyase activity,which increased by 180%and 90%,respectively.At the same time,the content of soluble sugar and total phenol in banana increased significantly,increasing by 190%and 18%,respectively.The above results indicate that Gi+GA₃ treatment is beneficial to promote plant growth,oxidation resistance and synthesis of sugars and phenols.But reduce the mycorrhizal infestation of bananas.?3?Ultra-high performance liquid chromatography?UPLC?was developed to detect the endogenous hormone content of bananas under four treatments.The detected system,methanol:0.1%acetic acid=45:55?v/v?,column temperature 30°C,wavelength 254 nm,injection volume of 5?L,flow rate of 0.4 mL/min,can effectively separate IAA,GA₃,ABA,SA.The test results are as follows:Brazilian carcass has the lowest abscisic acid content and the highest IAA content.In the Gi+GA₃ treatment,the IAA content was the highest.Compared with Gi+GA₃treatment,the contents of GA₃ and IAA increased significantly,increasing by 19%and 23%,respectively.The SA content was significantly reduced by 34%.Under gibberellin-mediated,the increase of GA₃ and IAA in banana mycorrhiza is conducive to the colonization of mycorrhiza.?4?By transcriptome sequencing technology,it was found that Gi+GA₃ treatment has an expression gene in the root of banana compared with GA₃ treatment.Statistically differential genes,a total of 2831 gene changes,1465 up-regulation and1366 down-regulation.The analysis of GO enrichment function showed that the differential genes had higher enrichment and significant difference in oxidative stress in biological processes.Molecular function mainly produces significant differences in antioxidantactivity.ThroughKEGGpathwayanalysis,phagocytosis,phenylpropanoid biosynthesis,phenylalanine metabolism,starch and sucrose metabolism,keratin,berberine and wax biosynthesis,flavonoid biosynthesis pathway differential gene in gibberellin-mediated mycorrhiza Significantly up-regulated in the process.Pathway-associated genes for plant hormone signaling are significantly downregulated.