Differentially expressed protein and gene analysis revealed the effects of temperature on changes in ascorbic acid metabolism in harvested tea leaves

Tea is an important non-alcoholic beverage worldwide.Tea quality is determined by numerous secondary metabolites in harvested tea leaves,including tea polyphenols,theanine,caffeine,and ascorbic acid(AsA).AsA metabolism in harvested tea leaves is affected by storage and transportation temperature.However,the molecular mechanisms underlying AsA metabolism in harvested tea leaves exposed to different storage and transportation temperature conditions remain unclear.Here we performed RP-HPLC to detect dynamic changes in AsA content in tea leaves subjected to high-(38°C),low-(4°C),or room-temperature(25°C)treatments.The AsA distribution and levels in the treated tea leaves were analyzed using cytological–anatomical characterization methods.The differentially expressed CsAPX1 and CsDHAR2 proteins,which are involved in the AsA recycling pathway,were identified from the corresponding proteomic data using iTRAQ.We also analyzed the expression profiles of 18 genes involved in AsA metabolism,including CsAPX1 and CsDHAR2.AsA was mainly distributed in tea leaf mesophyll cells.High-and low-temperature treatments upregulated the CsAPX1 and CsDHAR2 proteins and induced CsAPX and CsDHAR2 gene expression.These results indicated that the CsAPX1 and CsDHAR2 proteins might have critical roles in AsA recycling in tea leaves.Our results provide a foundation for the in-depth investigation of AsA metabolism in tea leaves during storage and transportation,and they will promote better tea flavor in tea production.

Integrative transcriptome,proteome,and microRNA analysis reveals the effects of nitrogen sufficiency and deficiency conditions on theanine metabolism in the tea plant(Camellia sinensis)

Nitrogen(N)is associated with amino acid metabolism in higher plants.Theanine is an important amino acid in tea plants.To explore the relationship between theanine metabolism and N conditions,we examined the differentially expressed genes(DEGs),proteins(DEPs),and microRNAs(DEMs)involved in theanine metabolism in tea plant shoots and roots under N sufficiency and deficiency conditions.Transcriptome,proteome,and microRNA analyses were performed on tea plant shoots and roots under N sufficiency and deficiency conditions.The contents of theanine,expression levels of genes involved in theanine metabolism,contents of proteinogenic amino acids,and activity of enzymes were analyzed.The DEP–DEG correlation pairs and negative DEM–DEG interactions related to theanine metabolism were identified based on correlation analyses.The expression profiles of DEGs and negative DEM–DEG pairs related to theanine biosynthesis were consistent with the sequencing results.Our results suggest that the molecular and physiological mechanism of theanine accumulation is significantly affected by N sufficiency and deficiency conditions.The DEGs,DEPs,and DEMs and the activity of the enzymes involved in theanine biosynthesis might play vital roles in theanine accumulation under N sufficiency and deficiency conditions in the shoots and roots of tea plants.

Species Investigation and Population Dynamic of Spiders in Tea Gardens in Northern Guangxi

A systematic investigation on spiders in a tea garden of Guilin Institute of Tea Sciences was conducted. The results showed that totally 687 specimens were collected, belonging to 34 species, 27genera, 14 families, 2 suborders, and a new record species Trochosa suiningensis in Guangxi was found. Spider is a ma- jor developing natural enemy group of insect pests in tea garden, with features of wide distribution, large quantity, long duration, strong predatory and stress resist- ance, which has strong predation on adults and nymphs of Empoasca vitis and young larvae of Ectropis oblique. The population of spiders in tea garden significantly increases after middle June, and reaches the peak in July and August every year.

CsWRKY13,a novel WRKY transcription factor of Camellia sinensis,involved in lignin biosynthesis and accumulation

Lignin is an aromatic polymer that provides the necessary mechanical strength for the transport of water and nutrients in higher plants.Lignin biosynthesis and accumulation affect growth and development of tea plants.The degree of lignification related to the tenderness of fresh tea leaves determines the quality of tea.WRKY transcription factors play central roles in plant development and physiological processes.However,the roles of WRKY transcription factors in lignin biosynthesis of tea plants remain unclear.In this study,a WRKY gene,CsWRKY13,was cloned from tea plant'Longjing 43'.The open reading frame(ORF)of CsWRKY13 gene was 708 bp,encoding 235 amino acids.Sequence analysis showed that CsWRKY13 contained a conserved WRKYGQK amino acid sequence and a zinc-finger-like motif CX4CX23HXH.Subcellular localization showed that CsWRKY13 was localized in the nucleus.The yeast trans-activation assay showed that CsWRKY13 had no transcriptional activity.Expression analysis showed that the CsWRKY13 gene was highly expressed in the stem.Overexpression of CsWRKY13 in Arabidopsis thaliana reduced lignin content and the expression levels of genes related to lignin biosynthesis in transgenic plants.Most flavonoids pathway related genes were significantly up-regulated.This study shows that CsWRKY13 might function as a negative regulator in regulation of lignin synthesis.