Makes Significant Progress in Reshaping the Growth Habits of Goji Berry

Goji berry (Lycium barbarum L.) is a perennial woody cash crop of high nutritional and medicinal value, boasting prominent industrial significance. However, its typical indeterminate inflorescence habit has become a major bottleneck constraining the industry's development. This trait causes goji branches to continuously sprout, bloom, and bear fruit in succession. Consequently, flowers and fruits at different developmental stages coexist on a single branch, making mechanized harvesting impossible. This severely limits the large-scale and industrialized development of goji berry cultivation.

In the breeding of some crops, selecting determinate growth germplasm characterized by terminal flowering, synchronized flowering and fruiting, and a compact plant architecture is an effective approach to achieving mechanized harvesting, reducing costs, and increasing efficiency. However, the molecular regulatory mechanisms underlying the determinate/indeterminate growth habits in goji berry remain unclear, which greatly hinders the targeted breeding of new goji varieties suitable for mechanized harvesting.

To address these industrial challenges, the Plant Resource Research and Development Team at the South China Botanical Garden, Chinese Academy of Sciences, constructed an F1 hybrid population of Lycium barbarum. They selected three key types of materials for their study: the indeterminate type (N), the determinate type before terminalization (TB), and the determinate type after terminalization (TA). Scanning electron microscopy (SEM) observations revealed significant differences in the shoot apical meristem development patterns between the two growth types (Figure 1). In indeterminate branches, the apex grows continuously; in contrast, in determinate branches, pre-terminal growth is similar to that of indeterminate branches, but shoot growth ceases once a terminal inflorescence meristem appears at the apex, shifting from vegetative to reproductive growth.

The research team further conducted comparative transcriptome analysis on the three experimental samples, screening 15 candidate genes regulating flowering and shoot apical determinacy in goji berry. They focused on functionally validating the SP-like family gene LbSP1 and LbSP5G1, the goji homolog of the tomato gene SlSP5G. Since a stable genetic transformation system for Lycium barbarum has not yet been established, the team turned to its close relative, black goji berry (Lycium ruthenicum), utilizing CRISPR/Cas9 gene-editing technology to successfully obtain single-knockout and double-knockout lines.

Phenotypic analysis demonstrated that LbSP1 and LbSP5G1 regulate goji plant architecture in a functionally complementary and differentiated manner (Figure 1). The LbSP1 single mutant formed terminal spike-like inflorescences and exhibited compact branches. The LbSP5G1 single mutant produced multi-flowered inflorescences, increased fruit set per branch, lost photoperiod sensitivity, and displayed overall earlier flowering. The LbSP1+LbSP5G1 double mutant integrated the superior traits of both single mutants, showing more compact architecture, earlier flowering, and higher inflorescence density. Quantitatively, the double mutant outperformed both single mutants and the wild type (WT) in all yield-related traits, achieving an average yield of 174.94 grams per plant—nearly three times that of the wild-type plants (approx. 55–65 grams)—while also possessing the highest fruit density per branch and per node. Protein interaction assays further revealed the mechanistic basis for this functional divergence, leading to the proposal of a PEBP core regulatory network (Figure 1): LbSP5G1 acts as a direct interaction hub, while LbSP1 serves as an environmental condition-dependent regulator, together balancing meristem maintenance and reproductive transition in goji berry.

Based on transcriptomics and gene-editing technology, this study identified and demonstrated that knocking out two conserved flowering regulatory genes, LbSP1 and LbSP5G1, can transform the indeterminate growth habit of goji branches into a compact, determinate structure, achieving synchronized flowering and increased yield. This provides a molecular framework for breeding compact goji varieties suitable for mechanized harvesting, marking a significant step forward in the modernization of goji crop improvement.

Recently, the related research findings, titled "CRISPR/Cas9-mediated knockout of LbSP1 and LbSP5G1 reveals efficient customization of shoot architecture in black goji berry," were published in the internationally authoritative journal Plant Biotechnology Journal. Dr. Fazal Rehman (postdoctoral fellow, now departed) and Assistant Researcher LIU Huanfang from the South China Botanical Garden, Chinese Academy of Sciences, are the co-first authors, with Researcher WANG Ying serving as the corresponding author. The co-authors include Master's graduate MA Yun, WU Yan, Researcher ZENG Shaohua, Associate Researcher YANG Chao, and Dr. ZONG Yuan from Hong Kong Baptist University. During the experiments, the research received assistance from Assistant Researcher LI Yuping, Master's student SHI Yi, and Professor CAO Xiaofeng from the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences. The study was funded by the National Natural Science Foundation of China, the Guangdong Science and Technology Program Project, the Strategic Priority Research Program of the Chinese Academy of Sciences, and the Guangdong Key Research and Development Program. Article link: https://doi.org/10.1111/pbi.70753

Figure. 1. Scanning electron microscopy observations of indeterminate and determinate shoot apices, and the effects of CRISPR/Cas9-mediated knockout of LbSP1 and LbSP5G1 on shoot apical meristem development and shoot architecture reprogramming in goji berry, reveal the central PEBP regulatory network underlying determinacy and high yield.

（Image by LIU Huanfang）