Research On Heat-shock Mediating Cuticle Metabolism To Regulate The Quality Characteristic Of Fresh-cut Lily Bulbs

Lily is one of the traditional medicinal and edible plants in China,and as a large lily resource country,there are about 55 species in China.Lanzhou lily bulbs as the only edible sweet lily,white and bright color,flesh fat,rich in nutrients and functional ingredients.However,lilies are prone to browning and decay after harvest,and the fresh-cut treatment exacerbates this phenomenon.Not only shorten the shelf life,affect the product sales,but also hinder the development of lily industry.Therefore,it is extremely important to control the quality of fresh-cut lily bulbs.In this study,the freshcut lily bulbs were treated with heat shock treatment(HT),coating treatment(CT),and heat shock combined with coating treatment(HT+CT).A systematic study was done on the changes of cuticle and cuticle,aiming to reveal the relationship between the cuticle and the storage quality of fresh-cut lily bulbs and provide a certain theoretical basis for the storage and preservation of fresh-cut lily.The specific research results are as follows:1.Compared with the control group,HT treatment can significantly inhibit the increase of the weight loss,decay rate and browning degree of lily bulbs during storage and maintain a higher whiteness.In addition,HT treatment can maintain the integrity of the cell membrane,hinder the dissolution of intracellular substances,and keep the bulbs with a certain content of soluble sugar and soluble protein,which cannot provide a suitable parasitic environment for pathogenic bacteria.At the same time,the activity of resistant enzymes such as peroxidase(POD)is maintained at a low level.Therefore,HT treatment can better maintain the quality of the storage period,delay the browning and decay of bulbs,and thus prolong the shelf life.2.The changes of wax and cutin in the cuticle of fresh-cut lily bulbs during storage were compared.The total wax content tended to decrease during storage,and a total of26 wax components were detected.They can be divided into fatty acids,alcohols,terpenoids and esters.The fatty acid content was the highest,occupying 65% of the total wax,followed by terpenoids,esters and alcohols.The content of keratin showed a trend of first increase and then decrease during storage,with a total of 19 horny monomers.Mainly fatty acids,but also cross-linked cinnamic acid derivatives and aromatic compounds.9,10,18-3hydroxy-octadecanoic acid was the most abundant horny monomer in lily bulbs.The components of the cuticle of lily bulbs treated with different treatments have been changing dynamically during storage.The HT-treated group maintained higher terpenes at the end of storage and had significantly higher cutin content throughout the storage period compared to the control group.3.Transcriptome analysis of the whole genome of fresh-cut lily bulbs in the control group and HT treatment group at different storage times.There were 10488 differential genes in CK＿0 vs CK＿20,8323 differential genes in CK＿0 vs CK＿40,7517 differential genes in CK＿0 vs R＿20,and 8542 differential genes in CK＿0 vs R＿40.The enrichment analysis showed that the main pathways related to the cuticle were fatty acid biosynthesis pathway,fatty acid extension pathway,phenylpropane biosynthesis pathway,sesquiterpene and triterpenoid biosynthesis pathway,cutin biosynthesis and ABC transport pathway.Special attention was paid to the fatty acid biosynthesis pathway,the fatty acid extension pathway,and the sesquiterpene and triterpenoid biosynthesis pathways.It was found that HT treatment could promote the expression of genes related to the fatty acid extension pathway.Some differential genes were selected for q RT-PCR verification and the results showed that the transcriptome Sequencing results are reliable.4.HT treatment can better maintain the quality of fresh-cut lily bulbs during storage,mainly through three aspects:(1)HT treatment can inhibit the activity of related browning enzymes during storage,so that lily bulbs maintain the original color and luster.(2)HT treatment is conducive to maintaining the integrity of the cell membrane,preventing the dissolution of intracellular substances,creating an epidermal environment that is not conducive to microbial infection,and reducing water loss.(3)HT treatment can change the components and functions of the cuticle by regulating the expression of genes involved in the synthesis and transcriptionthe of cuticle,thereby resisting various stresses during storage of lily bulbs.