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Article|24 Jul 2023|OPEN
Jujube witches’ broom phytoplasmas inhibit ZjBRC1-mediated abscisic acid metabolism to induce shoot proliferation
Fuli Ma1 ,† , Shanqi Zhang1 ,† , Yu Yao1,3 , Mengting Chen1,3 , Ning Zhang1 , Mingsheng Deng1 , Wei Chen1 , Chi Ma1 , Xinyue Zhang1 , Chenglong Guo1 , Xiang Huang1 , Zhenyuan Zhang1 , Yamei Li1,3 and Tingyi Li1 , Junyong Zhou1,2 , Qibao Sun2 , , Jun Sun,1 ,
1College of Horticulture, Anhui Agricultural University, 130 West Changjiang Road, Hefei City 230036, Anhui Province, China
2Horticulture Research Institute, Anhui Academy of Agricultural Sciences, 40 South Nongke Road, Hefei City 230031, Anhui Province, China
3State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Road, Hefei City 230036, Anhui Province, China
*Corresponding author. E-mail:,
Both authors contributed equally to the study.

Horticulture Research 10,
Article number: uhad148 (2023)
Views: 68

Received: 28 Apr 2023
Accepted: 13 Jul 2023
Published online: 24 Jul 2023


Jujube witches’ broom (JWB) phytoplasmas parasitize the sieve tubes of diseased phloem and cause an excessive proliferation of axillary shoots from dormant lateral buds to favour their transmission. In previous research, two JWB effectors, SJP1 and SJP2, were identified to induce lateral bud outgrowth by disrupting ZjBRC1-mediated auxin flux. However, the pathogenesis of JWB disease remains largely unknown. Here, tissue-specific transcriptional reprogramming was examined to gain insight into the genetic mechanisms acting inside jujube lateral buds under JWB phytoplasma infection. JWB phytoplasmas modulated a series of plant signalling networks involved in lateral bud development and defence, including auxin, abscisic acid (ABA), ethylene, jasmonic acid, and salicylic acid. JWB-induced bud outgrowth was accompanied by downregulation of ABA synthesis within lateral buds. ABA application rescued the bushy appearances of transgenic Arabidopsis overexpressing SJP1 and SJP2 in Col-0 and ZjBRC1 in the brc1-2 mutant. Furthermore, the expression of ZjBRC1 and ABA-related genes ZjHB40 and ZjNCED3 was negatively correlated with lateral main bud outgrowth in decapitated healthy jujube. Molecular evidence showed that ZjBRC1 interacted with ZjBRC2 via its N-terminus to activate ZjHB40 and ZjNCED3 expression and ABA accumulation in transgenic jujube calli. In addition, ZjBRC1 widely regulated differentially expressed genes related to ABA homeostasis and ABA signalling, especially by binding to and suppressing ABA receptors. Therefore, these results suggest that JWB phytoplasmas hijack the ZjBRC1-mediated ABA pathways to stimulate lateral bud outgrowth and expansion, providing a strategy to engineer plants resistant to JWB phytoplasma disease and regulate woody plant architecture to promote crop yield and quality.