| Konjac is a perennial herb of Amorphophallus in the Araceae family.Its underground stem is rich in nutrition,especially glucomannan.It is known as"magic food","gastrointestinal scavenger"and"blood purification agent",and it has been identified as one of the top ten health food by the World Health Organization.With the improvement of people’s daily living standard and health awareness,konjac health food is more and more popular,and the market is in short supply.In recent years,due to the implementation of the national targeted poverty alleviation project,the planting area of konjac in China now exceeds140,000 hm~2.However,the harvested corm has a long dormancy period,which rarely occurs in other crops.The long dormancy period of corm seriously affects the uniformity of seedling emergence in the field,resulting in different yields of harvested corm.At the same time,the longer dormancy period also increases the storage cost and storage risk of konjac corm.In order to explore the relationship between konjac corm dormancy and two endogenous hormones(abscisic acid and auxin),this study analyzed the content of ABA and IAA in konjac corm from deep dormancy period to germination period,studied the change rule,extracted the RNA of konjac corm during the whole process from dormancy corm to dormancy release corm,and established it with the knowledge of transcriptome cDNA library,comparative analysis of RNA in different stages of dormancy changes,in order to explore the different expression of hormone regulatory genes in the process of konjac corm dormancy to germination,and mining other candidate genes related to konjac dormancy and germination,provide a reference for the follow-up study of the molecular mechanism of konjac dormancy to germination transformation,and also provide a theoretical basis for the exploration of dormancy function genes and molecular breeding practice.The main findings are as follows:1.25℃is the most suitable storage temperature for the germination of konjac corm,which can make the corm break the dormancy in advance and start the growth of the buds.Meanwhile,25℃continuous treatment can make the germination rate of the corm in the same period at least 25%higher than other treatments,which can greatly adjust the uniformity of the germination of the corm buds.2.Abscisic acid(ABA)content was lower in the deep dormancy stage of corm,and rise to the highest value of 213 ng/g before the germination stage,and decline gradually after the sprouting stage,indicating that ABA played an important role in the maintenance of the dormancy of konjac corm;IAA increased significantly after the sprouting stage,reaching the maximum value of 33.8 ng/g,and decreased to 28 ng/g after the sprouting stage.The results showed that appropriate IAA could promote the rooting of corm.3.Three groups of konjac corm samples were successfully sequenced using the HiSeq2000 system(Illumina Inc.,USA)producing a large number of high-quality sequences,with an average of 44,854,388 reads for samples of dormancy period,44,854,388 for samples of dormancy period,47,118,799 for samples of germination.The unigenes sequences of konjac samples from three periods were compared in NR,GO,KEGG,eggNOG,Swissprot,Pfam,etc.Among them,91,934 unigenes were successfully annotated in the NR database,39,633 in the GO database,49,601 in the KEGG database,44,101 in the Pfam database,84,813 in the eggnog database,and 84,411 unigenes in the Swissport database.Through the comparative analysis of transcriptome in three stages,99 unigenes were differentially expressed in germination stage compared with dormancy stage;259 unigenes were differentially expressed in germination stage compared with dormancy stage;127 unigenes were differentially expressed in germination stage compared with germination stage,and there were a large number of differential gene expressions in the process of germination of konjac corms,indicating the polygenic regulation of genes related to dormancy and dormancy release of konjac corms.4.Based on the transcriptome analysis of konjac samples,47 genes related to ABA and224 genes related to IAA were detected.The expression of NCED-related genes and ABI3related genes in deep dormancy and bud germination was high,which promoted ABA synthesis and kept ABA content in corm at a relatively high level;the expression of CYP707-related genes in bud was high,which promoted ABA degradation and decreased ABA in corm;the expression of ARP-related genes in corm dormancy was high,which inhibited IAA The IAA content of konjac corm was relatively low during the period of deep dormancy and germination,while the expression of GH3-related genes was relatively high during the period of germination,which promoted the IAA synthesis. |
