Physiological and Transcriptome Analysis of ‘Gannan Zao' Navel Orange under Drought Stress
Welcome to Chinese Journal of Tropical Crops,

Chinese Journal of Tropical Crops ›› 2022, Vol. 43 ›› Issue (5): 893-903.DOI: 10.3969/j.issn.1000-2561.2022.05.003

• Omics & Biotechnology • Previous Articles     Next Articles

Physiological and Transcriptome Analysis of ‘Gannan Zao' Navel Orange under Drought Stress

LIU Linzhi1, OUYANG Huan1, LI Xingtao1,2, CHEN Jianmei1,2,*()   

  1. 1. School of Life Sciences, Gannan Normal University, Ganzhou, Jiangxi 341000, China
    2. National Navel Orange Engineering Research Center, Ganzhou, Jiangxi 341000, China
  • Received:2021-12-14 Revised:2022-01-09 Online:2022-05-25 Published:2022-05-30
  • Contact: CHEN Jianmei

Abstract:

The seasonal drought in the navel orange producing areas in China has a great impact on the yield and quality of navel orange. ‘Gannan zao' navel orange, a new variety, is widely popularized in navel orange producing areas in China. In order to deeply understand the drought tolerance of ‘Gannan zao' and explore its regulation mechanism on drought stress, the differences of photosynthesis and drought related physiological indexes between ‘Gannan zao' and ‘Newhall' under different drought stress were measured, and the transcriptional differences and the regulation of antioxidant enzyme gene expression were compared by RNA-seq analysis. The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of ‘Gannan zao' were significantly higher than those of ‘Newhall' under drought stress. With the increase of drought stress, the leaves of ‘Gannan zao' were more stretched than that of ‘Newhall', and the relative conductivity and malondialdehyde content of ‘Gannan zao' were significantly lower than that of ‘Newhall', while the activities of protective enzymes superoxide dismutase and peroxide dismutase changed more. There was no significant difference in soluble sugar content between ‘Gannan zao' and ‘Newhall'. After rehydration, the soluble sugar content of ‘Newhall' was significantly higher than that of ‘Gannan zao'. Transcriptome sequencing analysis showed that the number of DEGs between ‘Gannan Zao' and ‘Newhall' was 1266, 683 and 658 respectively at 0, 10 and 20 days of drought stress. Go enrichment analysis showed that the differential genes of ‘Gannan zao' were mainly concentrated in the process of cell protein modification, protein modification, polymer modification and phosphorus compound metabolism, while ‘Newhall' was not significantly enriched. KEGG enrichment analysis showed that the differential gene concentration pathways of ‘Gannan Zao' and ‘Newhall' were basically the same, while ‘Gannan zao' was also enriched in starch and sucrose pathway and amino acid and nucleotide sugar metabolism pathway. ‘Gannan zao' was also enriched in starch and sucrose pathway and amino acid and nucleotide sugar metabolism pathway. Both transcription factors were in ERF family, MYB family, NAC family, MYB_Related family, WRKY family, bHLH family, HB-other family, HSF family, B3 family and bZIP family were distributed. In addition, ‘Gannan zao' was specifically distributed in GRAS family. According to the transcriptome molecular results, 30 antioxidant enzyme related genes were screened, of which 48% were up-regulated and 52% were down regulated. The results of this study would provide a theoretical basis for the physiological changes of gannanzao in response to drought stress, and provide a molecular basis for the study of its drought resistance.

Key words: navel orange, drought stress, photosynthesis, enzymatic activity, malondialdehyde, transcriptome analysis

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