ABA Response Characteristics and the Regulatory Network of SPLs during Prunus armeniaca Fruit Ripening

doi:10.13560/j.cnki.biotech.bull.1985.2026-0040

Abstract

Abstract:

Objective This study aimed to investigate the expression patterns of PaSPLs during fruit ripening in apricot (Prunus armeniaca) and their molecular responses to exogenous abscisic acid (ABA) treatment. Additionally, we sought to identify the miRNAs that regulate PaSPLs, thereby providing a foundation for further exploring the mechanism by which ABA regulates fruit ripening through the miR156-PaSPL module. Method Using ‘Sungold’ as the experimental material, we identified members of the PaSPL gene family through bioinformatics approaches and analyzed their basic physicochemical properties, conserved motifs, phylogenetic relationships, and promoter cis-elements. The expression features of PaSPLs to exogenous ABA treatment were examined by quantitative real-time PCR (RT-qPCR). Subcellular localization of PaSPL proteins was verified via transient transformation of Nicotiana benthamiana leaves. Based on whole-transcriptome data, we constructed the miR156-PaSPL regulatory network and analyzed the expression patterns of miR156 and PaSPLs during apricot fruit ripening. In addition, the STRING database was used to predict PaSPL-interacting proteins. Result A total of 15 members of the PaSPL gene family were identified in apricot and classified into eight subfamilies. Promoter sequence analysis revealed four major categories of cis-elements involved in growth and development regulation. Expression analysis showed that during apricot fruit ripening, the transcript levels of PaSPL1 and PaSPL2 increased as ripening progressed. Their expression was further upregulated after exogenous ABA treatment and downregulated following NGDA (ABA biosynthesis inhibitor) treatment. In contrast, PaSPL9 exhibited the opposite expression pattern. Subcellular localization assays confirmed that PaSPL1, PaSPL2, and PaSPL9 were all localized in the nucleus. Using transcriptional and protein interaction prediction analyses, we constructed the miR156-PaSPL expression regulatory network and a PaSPL protein-protein interaction network. Conclusion A total of 15 PaSPLs were identified in apricot. Among them, PaSPL1 and PaSPL2 may positively promote fruit ripening, whereas PaSPL9 may exert an inhibitory effect. All three genes are responsive to ABA signals. Furthermore, miR156c may regulate fruit ripening by negatively modulating PaSPL9 expression. These findings provide a theoretical basis for elucidating the molecular mechanism underlying the synergistic regulation of fruit ripening by the miR156-SPL module and ABA.

Key words: apricot, fruit ripening, SPL gene family, ABA, miR156, bioinformatics, gene expression, regulatory network

ZHANG Yu-jing, CHEN Chen, GOU Ning-ning, JIANG Nan, WUYUN Ta-na. ABA Response Characteristics and the Regulatory Network of SPLs during Prunus armeniaca Fruit Ripening[J]. Biotechnology Bulletin, 2026, 42(11): 174-185.

Figures/Tables 8

Table 1 Function of SPL transcription factors in various plant species

物种 Species	基因 Gene	功能 Function	拟南芥同源基因 Arabidopsis ortholog gene	杏同源基因 Apricot ortholog gene
香蕉 Musa acuminata	MaSPL1	果实成熟	AtSPL3/4/5	PaSPL11/12
	MaSPL16	果实成熟	AtSPL13	PaSPL4/9
蓝莓 Vaccinium spp.	VvSPL2	果实成熟	AtSPL2/10/11	PaSPL5
苹果 Malus domestica	MdSPL6	株型	AtSPL6	PaSPL6
	MdSPL13B	单性结实	AtSPL13	PaSPL4/9
柑橘 Citrus reticulata	CiSPL2	果实成熟	AtSPL2	PaSPL5
	CiSPL3	株型	AtSPL3/4/5	PaSPL11/12
	CiSPL6	株型	AtSPL6	PaSPL6

Fig. 1 Phylogenetic tree of SPL family proteins in Prunus armeniaca 'Sungold', P. sibirica 'F106', P. armeniaca × P. sibirica 'LWM', Arabidopsis thaliana, Solanum lycopersicum, P. avium and P. persica

Fig. 2 Conserved motif analysis of the PaSPLs gene family in P. armeniaca

Fig. 3 Collinearity analysis of PaSPLs genes within species (A) and between species (B) in P. armeniaca

Fig. 4 Analysis of the cis-elements in the promoter region of the PaSPL gene family in P. armeniaca

Fig. 5 Changes in the expression of PaSPLs in P. armeniaca at different developmental stages (A) and in response to exogenous ABA treatment (B)GF-1: 63 DAFB, green fruit stage-1; GF-2: 70 DAFB, green fruit stage-2; TF: 74 DAFB, turning fruit stage; RF: 84 DAFB, ripening fruit stage. Different letters indicate significant differences at 0.05 level (P < 0.05). The same below

Fig. 6 Subcellular localization (A) and protein interaction analysis (B) of PaSPL in P. armeniaca

Fig. 7 Analysis of target site prediction and regulatory network of miR156-PaSPLs in P. armeniacaA: Alignment of mature sequences of seven miR156 family members. B: miR156 target sites in PaSPL4/5/6/8/9/14/15 genes. Yellow boxes represent the coding sequences (CDS) of PaSPLs genes, purple boxes represent the SBP domain, and blue boxes represent the miR156 target sites. C: Regulatory network between miRNAs and PaSPLs genes. D: Expression variation of miRNAs in common apricot at different developmental stages

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