Transcriptomic and physiological comparison of Shatangju (Citrus reticulata) and its late-maturing mutant provides insights into auxin regulation of citrus fruit maturation

Aug 25, 2026

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Compares genome-wide gene expression profiles and parallel changes in hormones and peel pigments between Shatangju mandarin (Citrus reticulata, WT) and its natural late-maturing mutant Yuenongwanju (MT). MT fruits mature about two months later and show significant genotype-dependent differences in fruit size, soluble solids, titratable acids, chlorophylls, and carotenoids. Transcriptome results highlight altered expression in auxin and ABA pathways, with CrYUCCA8 lower and CrNCED5 higher in WT than MT at defined DPA stages. IAA is higher in MT while ABA is lower; exogenous IAA delays maturation, supporting auxin as a negative regulator of citrus fruit maturation.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages15

Reading Time38 min

AccessFree to download

Introduction

Materials and methods

Results

Transcriptomic profiling and differential expression

Hormone and pigment changes

Discussion

Conclusion

UC Davis UC Davis Previously Published Works Title Transcriptomic and physiological comparison of Shatangju (Citrus reticulata) and its late-maturing mutant provides insights into auxin regulation of citrus fruit maturation Permalink [https://escholarship.org/uc/item/25q9n416](https://escholarship.org/uc/item/25q9n416) Journal Tree Physiology, 43(10) ISSN 0829-318X Authors Lv, Yuanda Ren, Shuang Wu, Bo et al. Publication Date 2023-10-08 DOI 10.1093/treephys/tpad089 Peer reviewed [eScholarship.org](eScholarship.org) Powered by the California Digital Library University of California Tree Physiology 43, 1841–1854 [https://doi.org/10.1093/treephys/tpad089](https://doi.org/10.1093/treephys/tpad089) Research paper Transcriptomic and physiological comparison of Shatangju (Citrus reticulata) and its late-maturing mutant provides insights into auxin regulation of citrus fruit maturation Yuanda Lv 1 ,†, Shuang Ren 1 ,†, Bo Wu 1 ,†, Caizhong Jiang2 , Bo Jiang 1 , Birong Zhou 1 , Guangyan Zhong 1 , Yun Zhong 1 and Huaxue Yan1 , 3 1 Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences/Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization, Ministry of Agriculture and Rural Affairs/Guangdong Provincial Key Laboratory of Tropical and Subtropical Fruit Tree Research, No. 80, Dafeng No. 2 street, Tianhe District, Guangzhou 510650, Guangdong Province, China; 2 Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA; 3 Corresponding author ([yanhuaxue@gdaas.cn](yanhuaxue@gdaas.cn)) Received January 12, 2023; Accepted July 9, 2023; handling Editor Heather Coleman Previous studies have shown that abscisic acid (ABA) and ethylene are involved in pulp maturation and peel coloration in the nonclimacteric citrus fruits. There are also signs indicating that other plant hormones may play some roles in citrus fruit ripening. In this study, we compared profiles of genome-wide gene expression and changes in hormones and peel pigments between fruits of Shatangju mandarin (Citrus reticulata Blanco, designated WT) and its natural mutant, Yuenongwanju (designated MT). The MT fruit matures ∼2 months later than the WT fruit. Significant differences in fruit diameter, total soluble solids, titratable acid content, chlorophylls and carotenoids were detected between the fruits of the two genotypes at the sampled time points. Genome-wide transcriptome profiling showed that many genes involved in auxin and ABA metabolism and/or signaling pathways were differentially expressed between the MT and the WT fruits. Importantly, the expression of CrYUCCA8 was significantly lower and the expression of CrNCED5 was significantly higher in WT than in MT fruits at 230 and 250 DPA, respectively. In addition, the indole-3-acetic acid (IAA) level in the MT fruit was significantly higher than that in the WT counterpart, whereas a significantly lower level of ABA was detected in the mutant. Treatment of the WT fruit with exogenous IAA significantly delayed fruit maturation. Our results provide experimental evidence supporting the notion that auxin is a negative regulator of fruit maturation in citrus. Keywords: Citrus fruit, auxin, carotenoid, maturation, transcriptome. Introduction The maturation of citrus fruit is coupled with significant changes both in peel color and in pulp sugar and acid content. The process is believed to be triggered and regulated by external and internal stimuli (Iglesias et al. 2001) . Known plant hormones involved are ethylene, abscisic acid (ABA) and gibberellins (GAs) (Stewart and Wheaton 1972, Porat et al. 2001, Rodrigo et al. 2003) . Ethylene does not trigger an autocatalytic ethylene production and a corresponding respiration peak in the nonclimacteric citrus fruits as it does in apple, banana and other climacteric fruits. Yet, ethylene does trigger color changes in citrus fruit peel (Stewa

FAQs

What organisms and genotypes were compared in the study?

The study compared Shatangju mandarin (Citrus reticulata, WT) with its natural late-maturing mutant Yuenongwanju (MT). Both were analyzed for transcriptomic, hormonal, and peel-pigment changes across maturation stages.

How did the mutant’s maturation timing differ from the wild type?

MT fruits matured approximately two months later than WT fruits. Differences in fruit traits and biochemical composition were measured at sampled time points.

What hormone and gene expression patterns were linked to delayed maturation?

The work found altered auxin and ABA metabolism/signaling gene expression between MT and WT. Specifically, CrYUCCA8 expression was lower and CrNCED5 expression higher in WT than in MT at 230 and 250 DPA, respectively, with MT showing higher IAA and lower ABA levels.

What experimental evidence supports auxin as a regulator of citrus fruit maturation?

Applying exogenous IAA to WT fruits significantly delayed fruit maturation. Combined with hormone and gene-expression contrasts, the results support auxin functioning as a negative regulator of citrus fruit maturation.

Aug 25, 2026

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