Expression Analysis Of Plant Hormone Related Genes During The Process Of Secondary Floral Bud Formation In Mangoes

In most regions of China,mangoes（Mangifera indica L.）enter the flowering period from mid to late December to mid March,when late spring coldness occurs frequently.Low temperature,overcast and rainy weather has affected mangoes,leading to a decline in yield and quality.By removing mango flower spikes,it can undergo secondary floral bud differentiation,effectively avoiding adverse weather and ensuring mango yield.Plant hormone-related genes have a crucial regulatory role in the process of floral bud formation.Therefore,this study used’Guifei’mango floral buds as experimental materials to explore the regulatory mechanism of plant hormone related genes in the process of secondary floral bud formation of mango after picking flowers through transcriptome sequencing technology,providing a reference for preliminary research on floral bud induction.The research results are as follows:1.Flower picking technology can effectively regulate mango lateral buds for floral bud differentiation,and this phenomenon has reproducibility and stability.2.The enrichment analysis results show that the plant hormone signal transduction pathway is the most enriched gene pathway,and there are also many genes enriched in plant hormone synthesis related pathways.Among them,IAA related genes TAA1,YUCCA and TIR1;CTK related genes CYP735A and A-ARR;GA synthesis genes GA₂₀ox and GA₃ox;ABA signal gene ARF;Ethylene synthesis gene ACS;BL related genes DWF4,BRI1and CYCD3;JA signal genes MYC2 and JAZ;SA synthesis gene PAL,the expression levels of these genes all increaseare after picking flowers.And CTK synthesis gene IPT;GA related genes KAO,DELLA and GID1;ABA related genes ABA2 and Sn PK2;ETH signal genes MPK6,EIN2 and EIN3;JA related genes AOX and JAR1;SA signal genes NRR1 and TGA,the expression levels of these genes decreased after flower picking treatment.This indicates that flower picking measures may regulate the secondary floral bud formation of mangoes by affecting the expression of these genes.3.There were significant differences in the expression levels of ARF and DELLA genes during the secondary floral bud formation process of mangoes.In the process of flower bud formation,the LOC123213085 gene in ARF is mainly highly expressed in the middle and late stages of flower bud formation（T2,T3）,which is 4.5 times higher than that in the early stage of the same group（T1）;the expression level of DELLA gene was highest in the late stage of formation（T3）of flower buds in the treatment group.Indicating that high expression of these two genes in the later stage of formation may be beneficial for their transfer into flower bud morphological differentiation.4.The flower picking measures in this study may regulate the secondary floral bud formation of mangoes by affecting CTK hormone signaling gene.After flower picking treatment,the expression level of the cytokinin signaling gene B-ARR（LOC123217369）significantly increased.The expression level of this gene in the late stage（CK3）and middle stage（CK2）of the control group was 2.92 and 2.21 times higher than that in the late stage（T3）and late stage（T2）of the treatment group,respectively.Indicating a decrease in B-ARR gene expression,weakening its negative regulatory effect,and promoting the formation of mango secondary floral buds.However,its functionality still needs further verification.