Differences in leaf cuticular wax induced by whole-genome duplication in autotetraploid sour jujube

Drought-resistant plants exhibit strong water retention capability.In this regard,the autotetraploid sour jujube leaves exhibit better water retention than diploid leaves.Morphological comparisons and physiological comparisons of diploid and autotetraploid leaves showed that the autotetraploid leaves had thicker leaf cuticles and more leaf wax accumulation than the diploid leaves,which could reduce cuticle permeability and improve the drought tolerance of leaves.In this study,the cuticular wax crystalloids on the adaxial and abaxial sides of young and mature jujube leaves were observed in the two ploidy types,and unique cuticular wax crystalloids covering a large area of the cuticle on autotetraploid sour jujube leaves may provide an advantage in reducing leaf non-stomata transpiration and improving plant drought tolerance.Based on the transcriptome,115 differentially expressed genes between diploids and autotetraploids were further analyzed and found to be involved in the accumulation of cuticular wax components,including terpenoids,fatty acids,and lipids,as well as ABC transporter and wax biosynthetic process.Finally,14 genes differentially expressed between glossy autotetraploid leaves and nonglossy diploid leaves,such as LOC107414787,LOC107411574 and LOC107413721,were screened as candidate genes by qRT-PCR analysis.This findings provided insights into how polyploidization improved drought tolerance.

Genome-wide identification and analysis of the DREB genes and their expression profiles under abiotic stresses in Chinese jujube(Ziziphus jujuba Mill.)

CBF/DREB proteins play a critical role in abiotic stress-mediated gene expression and represent attractive regulons for plant breeding programs.However,no study has been conducted for CBF/DREB protein-related genes in jujube(Ziziphus jujuba Mill.).In this study,twenty-five ZjDREB genes were identified and annotated from the jujube(Z.jujuba‘Dongzao’)genome.Detailed analysis,including gene classification,annotation,phylogenetic evaluation,conserved motif determination and expression profiling were performed on all genes.Phylogenetic analysis showed that ZjDREB proteins were divided into five subgroups(A1–A5),but lacking a subgroup A6 corresponding to AtDREBs.The ZjDREB genes were distributed in nine of twelve chromosomes in the genome.Additionally,the expression patterns of the DREB genes under different abiotic stresses were investigated using q RT-PCR.Nineteen ZjDREB genes were down-regulated under low temperature,in contrast six ZjDREB genes(01,03,05,11,23 and 24)were up-regulated.Under drought,salinity and high temperature conditions,expression of ZjDREB03,09,10,14,15,17 and 20 genes were induced and showed similar expression patterns,suggesting that various stress conditions share common elements in the signaling pathway.The results suggest that the family of DREB genes play an important role in abiotic stresses in jujube,and provide a foundation for further functional studies of this important class of transcriptional regulators.

Comparative transcriptome analysis identifies differentially expressed genes between normal and late-blooming Siberian apricot

Blooming date is an important trait in fruit tree species.Although several quantitative trait loci confirming blooming date were identified in Prunus spp.,the molecular mechanism underlying it remains unclear.Arising from this,the transcriptomes of normal blooming and lateblooming Siberian apricot(P.sibirica L.)flower buds were analyzed using RNA-seq technology.A total of 68,855 unigenes were de novo assembled,among which 1204 were differentially expressed between normal and late blooming.Gene ontology enrichment analysis revealed that biological processes were enriched with metabolic processes.The catalytic-related gene transcripts between the two types of blooming were significantly changed in the molecular function.Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 156 genes were successfully annotated and 75 pathways enriched.Genes for gibberellin biosynthesis were up-regulated in normal blooming,whereas abscisic acid degradation-related genes were also up-regulated in normal blooming.Moreover,circadian rhythms related genes including EARLY FLOWERING 4,LATE ELONGATED HYPOCOTYL and CIRCANDIAN CLOCK ASSOCIATED1 were all up-regulated in normal blooming,indicating that circadian rhythms have a very important role in controlling blooming date.Furthermore,zinc finger protein CONSTANS-LIKE 12 was blasted onto the quantitative trait loci region on linkage group 4 in peach.However,changes in the abundance of key flowering genes such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1,FLOWERING LOCU T,LEAFY and FLOWERING LOCUS C were not significantly different,indicating that further investigation should explore the function of these genes on blooming date.The outcomes of this study will provide a valuable platform for further research on the molecular mechanism of blooming date in Prunus.