@Article{phyton.2026.072636,
AUTHOR = {Xiaofeng Mao, Fenni Lv, Shaofeng Li, Lulu Gao, Wenjun Ma, Donglai Liu, Binpeng Wu, Yanan Wu, Peng Wang, Naiwei Li},
TITLE = {Gene-Specific Effects of Three <i>Cry</i> Transgenes on Rhizosphere Microbiota in <i>Catalpa bungei</i>},
JOURNAL = {Phyton-International Journal of Experimental Botany},
VOLUME = {95},
YEAR = {2026},
NUMBER = {2},
PAGES = {0--0},
URL = {http://www.techscience.com/phyton/v95n2/66466},
ISSN = {1851-5657},
ABSTRACT = {<i>Catalpa bungei</i>, a fast-growing timber tree, is threatened by the lepidopteran pest <i>Omphisa plagialis</i>. Previous studies in our laboratory successfully generated transgenic <i>C. bungei</i> lines overexpressing <i>Cry</i> genes (<i>Cry1Ab</i>, <i>Cry2A</i>, and <i>Cry9-2</i>) that exhibited resistance to <i>O. plagialis</i>, but their potential impact on soil bacterial communities remains unclear. In this study, we analyzed nine transgenic <i>C. bungei</i> lines (three independent lines for each <i>Cry</i> gene) to characterize their rhizosphere bacterial communities using high-throughput sequencing of the 16S ribosomal DNA (rDNA) V4–V5 regions. A total of 628 amplicon sequence variants (ASVs) were shared among all transgenic and wild-type (WT) lines, forming a stable core microbiome dominated by Proteobacteria, Bacteroidota, Acidobacteriota, and Actinobacteriota. Alpha diversity showed no significant differences, while beta diversity revealed minor but distinct compositional shifts. <i>Cry1Ab</i> lines exhibited higher abundances of fast-growing taxa, particularly Proteobacteria and Bacteroidota; <i>Cry2A</i> lines displayed intermediate profiles, whereas <i>Cry9-2</i> lines were nearly indistinguishable from WT communities. Linear discriminant analysis of the effect size revealed significant enrichment of taxa such as Burkholderiaceae and <i>Ralstonia</i> in the <i>Cry1Ab</i> rhizosphere, in contrast to the higher abundance of Chloroflexi in the WT. Functional predictions indicated consistent metabolic pathways across all treatments, suggesting strong ecological redundancy. This study demonstrates minimal impact on rhizosphere microbial communities in transgenic <i>C. bungei</i> plants. The <i>Cry9-2</i> construct exhibited superior environmental stability, whereas the <i>Cry1Ab</i> construct caused only slight but ecologically acceptable shifts. These findings support the ecological safety of <i>Bt</i>-transgenic <i>C. bungei</i> and identify <i>Cry9-2</i> as a particularly favorable candidate for forestry applications. This comparative evaluation of three <i>Cry</i> genes in a tree species provides a framework for future gene-specific biosafety assessments in woody plants.},
DOI = {10.32604/phyton.2026.072636}
}