Physiological responses and transcriptomic profiles unveil pivotal genes and pathways implicated in nano-elicited in vitro shoot proliferation of Bambusa balcooa

Abstract

Bamboos are perennial, arborescent, monocarpic, and industrially important non-timber grasses that are used as a pristine source of inorganic nutrients. However, conventional vegetative propagation methods demonstrated inadequate multiplication potential. This study investigates how Bambusa balcooa’s in vitro growth, photosynthetic pigment content, and antioxidant capacity were affected by citrate- and cetyltrimethylammonium bromide-coated gold nanoparticles (AuNPs). Further, to unravel the regulatory mechanism underlying gold nano-elicitation and in vitro plant behavior, we conducted RNA sequencing of non-treated control, 400 µM citrate-AuNPs-treated, and 600 µM CTAB-AuNPs-treated plantlets. Numerous morphological, physiological, and biochemical parameters were observed to be variably impacted along the citrate- and CTAB-coated AuNPs concentration gradient (200–600 µM). B. balcooa in vitro shoots supplemented with Murashige and Skoog medium enriched with 6-benzylaminopurine, naphthaleneacetic acid, and 400 µM citrate-AuNPs displayed statistically significant shoot proliferation, photosynthetic pigment accumulation, and antioxidant activities. Contrarily, a decline in growth parameters was observed in MS media supplemented with BAP, NAA, and 600 µM CTAB-AuNPs. Transcriptome profiling revealed various differentially expressed genes (DEGs) and metabolic pathways associated with nano-elicitation and plant growth. Furthermore, identifying genes (such as Glyoxalase, Expansin, and ZAT) governing in vitro proliferation and oxidative stress responses could enhance our understanding of the mechanisms underlying AuNPs’ ability to modulate various physiological and biochemical activities during micropropagation. Therefore, gene ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, and the exploration of DEGs involved in the in vitro modulations regulated by AuNPs offer novel insights into the molecular mechanisms governing nano-elicited plant organogenesis more comprehensively.

Graphical abstract