缺硝态氮胁迫茶树根尖转录组及调控网络解析OA

Nitrate(NO-3)is one of the major nitrogen sources for tea plant growth and development,and fluctuations in its supply directly affect nitrogen metabolic homeostasis and tea quality formation.To elucidate the molecular mechanisms underlying the response of tea plants to NO-3 deficiency,the cultivar"Longjing 43"was subjected to a time course treatment(0-12 h).Physiological measurements were integrated with transcriptome sequencing and qPCR validation to characterize the dynamic responses to NO-3 deprivation.The results showed that short term NO-3 deficiency significantly reduced leaf Fv/Fm and free amino acid contents,accompanied by simultaneous decreases in root NO-3 and NH+4 contents,indicating inhibition of photosynthetic performance and nitrogen metabolism.A total of 2,407 differentially expressed genes(DEGs)were identified.GO and KEGG enrichment analyses revealed that these DEGs were mainly involved in carbohydrate metabolism,stress responses,phenylpropanoid and flavonoid biosynthesis,plant hormone and MAPK related signaling pathways.The nitrate reduction and transport related genes CsNiR and CsNPF5.7 were consistently downregulated,suggesting suppression of primary nitrogen assimilation,whereas CsGDH2.1 and CsAS were significantly upregulated,indicating that tea plants may enhance their tolerance to nitrogen deficiency through coordinated regulation of carbon-nitrogen metabolism and stress related signaling.This study reveals the molecular regulatory patterns of tea plants under NO-3 deficiency and provides a theoretical basis for elucidating nitrogenuse efficiency mechanisms and identifying candidate functional genes in tea plants.