Returning straw derived biochar back to the farmland has been widely recognized as a sustainable agricultural strategy to improve soil quality and fertility. The molecular mechanism underlying the growth promoting effects of tobacco (Nicotiana tabacum L.) straw biochar on tobacco remains unclear. A pot experiment was carried out to investigate the effects of tobacco straw biochar on root morphology, photosynthesis and nutrient uptake of tobacco plants. Biochar stimulated root growth and altered root morphology. In addition, biochar significantly improved leaf net photosynthetic rate, water use efficiency, and contents of chlorophyll a, chlorophyll b, and carotenoid. Tobacco plants treated with biochar exhibited significantly greater plant dry weight and higher uptake of total nitrogen, phosphorus, and potassium than the control plants. The transcriptome analysis indicated that biochar application led to changes in the expression levels of genes involved in transmembrane transport and zeatin biosynthesis and cell wall loosening in roots, upregulation of photosynthesis-related genes and TF genes (G2-like, MADS-box, and NF-YB), and downregulation of TF genes (HSF, ERF, NAC, and WRKY). Biochar application induced marked changes in the metabolite profiles in roots and leaves. Combined metabolome and transcriptome analysis revealed that biochar application mainly affected stilbenoid, diarylheptanoid and gingerol biosynthesis pathway in roots. This study offers new insights into the mechanism of tobacco straw biochar-induced growth promotion in tobacco plant and establishes a strong foundation for its application in tobacco industry and sustainable agriculture.
Chen et al. (Tue,) studied this question.