Analysis Of Amygdalin Metabolism In Seed Germination Of Three Wild Species Of Almond

Amygdalus subgenus of Rosaceae distributes six species in China,and five of them are wild species,which are mongolic almond,longstalk almond,tangut almond,flowering almond,and wild almond.The one cultivar is common almond.Amygdalin is the main bitter substance in Amygdalus subgenus,whose content is low in common almond,but rich and various in wild species.There are more studies on the metabolic mechanism of amygdalin in cultivar at home and abroad,and few studies on the other wild species.However,the wild species have higher content of amygdalin,greater difference and more abundant resources,so it is more valuable to study the metabolic regulation mechanism of amygdalin in five wild almond species in China.This study was based on the response mechanism of amygdalin in seed germination on mongolic almond,longstalk almond and tangut almond,researching the effect of amygdalin content change in germination,and the influence of water content and regularity of amygdalin content.Especially through the transcriptome analysis,the change rule of amygdalin differences in seed germination of three wild almonds were analyzed.It is further revealed the correlative mechanism of difference of expression in key enzyme,and preliminary illustrated the metabolic mechanism that amygdalin in germination.In this study,the germination test of three almonds was conducted to quantitatively analyze amygdalin contents and synthetic genes expression,as well as analysis of correlation,differential expression and gene sequence mutations.The results showed that kernel water content promoted germination when reaching 30%.The maximum range of amygdalin contents during 6d～13d is1.46g/100g in longstalk almond.2^-ΔΔCT expression quantity of CYP79D16 in tangut almond has biggest change（0.2～292.5）.UGT95A19 showed the highest expression of glucosyltransferase（10.9）,and UGT94s in germination（10d～16d）was regulated to decrease;In the synthetic gene sequence,SNPS were more frequent in glycosyltransferase genes,and the location were distributed in the upstream and downstream genes and the translation region,etc.There were the most SNPS in tangut almond（115）,and the least in longstalk almond（46）,that the SNPs showed a interspecific affinity.Non-synonymous mutations are abundant in tangut almond（30）,and UGT94AF1 contains the most locations.The up-regulated differentially expressed genes after germination were significantly enriched in phenylalanine metabolism and cyanoamino acid metabolism.It was concluded that the changes in amygdalin content during germination were closely related to the metabolic activities and the nitrogen transfer pathway,and the up-regulation of genes in the metabolic pathway caused the changes in content and the increase in nitrogen transfer.The reason of the contents difference in wild almonds may be related to the difference of glycosyltransferase.In this study,the response and difference of enzymes related to the regulation of amygdalin content in three wild species were discussed from the level of seed germination,which can be used as a reference for further study on the difference of amygdalin content and the regulation mechanism of development anabolic metabolism in wild species of almond.