Overexpression of the Peach Transcription Factor Early Bud-Break 1 Leads to More Branches in Poplar

Abstract

Shoot branching is an important adaptive trait that determines plant architecture. In a previous study, the Early bud-break 1 (EBB1) gene in peach (Prunus persica var. nectarina) cultivar Zhongyou 4 was transformed into poplar (Populus trichocarpa). PpEBB1-oe poplar showed a more branched phenotype. To understand the potential mechanisms underlying the EBB1-mediated branching, transcriptomic and proteomics analyses were used. The results showed that a large number of differentially expressed genes (DEGs)/differentially expressed proteins (DEPs) associated with light response, sugars, brassinosteroids (BR), and nitrogen metabolism were significantly enriched in PpEBB1-oe poplar. In addition, contents of sugars, BR, and amino acids were measured. Results showed that PpEBB1 significantly promoted the accumulation of fructose, glucose, sucrose, trehalose, and starch. Contents of brassinolide (BL), castasterone (CS), and 6-deoxocathasterone (6-deoxoCS) were all significantly changed with overexpressing PpEBB1. Various types of amino acids were measured and four of them were significantly improved in PpEBB1-oe poplar, including aspartic acid (Asp), arginine (Arg), cysteine (Cys), and tryptohpan (Trp). Taken together, shoot branching is a process controlled by a complex regulatory network, and PpEBB1 may play important roles in this process through the coordinating multiple metabolic pathways involved in shoot branching, including light response, phytohormones, sugars, and nitrogen.

Knockdown of PagSAP11 Confers Drought Resistance and Promotes Lateral Shoot Growth in Hybrid Poplar (Populus alba × Populus tremula var. glandulosa)

“…In contrast, the transcript levels of RAX1, which encodes an MYB transcription factor involved the initiation of axillary meristems ( Jia et al, 2020) were increased in SAP11-Ri. Furthermore, the expression levels of DML10, a gene involved in bud break (Conde et al, 2019), and CYP707A, a gene related to bud dormancy (Zhao et al, 2021), were also upregulated in SAP11-Ri. However, the mRNA abundance of DRM, a marker of bud dormancy (Yoon et al, 2017), was decreased in SAP11-Ri compared with the WT plants (Figure 5).…”

When to branch: seasonal control of shoot architecture in trees

“…In shoot branching, sugar signals are more strongly involved in activation of dormant buds than in seasonal growth, sugar fluxes can mimic decapitation effects, and sugars rapidly accumulate in axillary buds after decapitation [33]. A recent study showed that the overexpression of the peach Early bud‐break 1 ( PpEBB1 ) gene in poplar leads to the formation of more branches by differentially regulating the genes and proteins involved in light response, brassinosteroid signaling and nitrogen metabolism [17]. Further analysis of PpEBB1oe plants also revealed the accumulation of various sugars, such as fructose, glucose, sucrose, trehalose and starch, which were correlated with an increased number of branches.…”

“…These plants present several advantages for their investigation, including a short life cycle, available genome sequences, wellunderstood genetic properties and a convenient size [11][12][13]. However, they cannot provide information on key aspects of perenniality, and so, in recent years, studies have been extended to many perennial model systems, such as Arabis alpina, rose, apple, grapevine, peach, and several species and hybrids of Populus (hereafter poplars) [14][15][16][17][18][19][20][21]. In many of the plants noted above, studies of shoot branching regulation have focused on the effects of apical dominance on branching, largely in classical decapitation experiments, rather than effects of seasonal regulation, and so the key questions remain unanswered.…”

Jasmonic acid negatively regulates branch growth in pear

“…Bud mutation is an important means of causing changes in branching through plant somatic variation ( Zhao et al., 2021 ). The meristem cells of buds undergo genetic changes during cell division, leading to the development of lateral branches ( Leng et al., 2021 ).…”