Transcriptome Profiles Reveal the Growth-Promoting Mechanisms of Paenibacillus polymyxa YC0136 on Tobacco (Nicotiana tabacum L.)

Abstract

Paenibacillus polymyxa is an important member of the plant growth-promoting rhizobacteria. P. polymyxa YC0136 inoculation had beneficial effect on growth promotion and biological control of tobacco (Nicotiana tabacum L.) under field conditions. This study aimed to reveal the growth-promoting mechanisms of strain YC0136. In growthpromotion assays, tobacco plant height was increased by 8.42% and 8.25% at 60 and 90 days, respectively, after inoculation with strain YC0136. Strain YC0136 also promoted the accumulation of tobacco biomass in varying degrees. Following inoculation with strain YC0136, 3,525 and 4,368 tobacco genes were up-regulated and down-regulated, respectively. Strain YC0136 induced the expression of plant hormone-related genes in tobacco, including auxin, cytokinin, and gibberellin, as well as transcription factors related to stress resistance such as WRKY and MYB. In addition, strain YC0136 induced the up-regulation of genes in the phenylpropanoid biosynthesis pathway by 1.51-4.59 times. Interaction with tobacco also induced gene expression changes in strain YC0136, with 286 and 223 genes up-regulated and down-regulated, respectively. Tobacco interaction induced up-regulation of the ilvB gene related to auxin biosynthesis in strain YC0136 by 1.72 times and induced expression of some nutrient transport genes. This study contributes to our understanding of the growth-promoting mechanisms of strain YC0136 on tobacco and provides a theoretical basis for the application of P. polymyxa YC0136 as a biological fertilizer.

Roles of Plant Growth-Promoting Rhizobacteria (PGPR) in Stimulating Salinity Stress Defense in Plants: A Review

“…In response to host rice seedlings, Bacillus subtilis OKB105 also altered its transcriptomic patterns, in which 52 genes related to nutrients transport and metabolism were upregulated, suggesting the bacterium used carbohydrates and amino acids secreted by rice seedlings as carbon and energy sources. In contrast to the data in [ 163 ], many genes involved in chemotaxis and motility, however, were downregulated [ 173 ].…”

“…Malviya et al [ 170 ] also found that the infection of Burkholderia anthina MYSP113 into the sugarcane plantlets cv. GXB-9 induced the upregulation of phenylpropanoid biosynthesis genes and amino acid biosynthesis pathways, in accordance with the findings from Liu et al [ 163 ]. Likewise, phenylpropanoid biosynthesis was the most enriched pathway in both differentially expressed genes (DEGs) and abundant metabolites (DAMs) among all salt stress responses in barley rootzones [ 171 ].…”

“…In all treatments, the expression levels of AEs-encoding genes POD and CAT were the highest in the P. simiae + SNP-treated soybean plants [ 147 ]. Genes associated with Aux, CK, and GA signaling pathways in the Paenibacillus polymyxa YC0136-treated tobacco plants ( Nicotiana tabacum L.) were found to be upregulated relative to the uninoculated control plants, along with the elevated expression of WRKY and MYB transcription factors (TFs) [ 163 ]. The WRKY and MYB TFs are responsible for gene regulations and have a great influence in every aspect of plant growth and development, as well as in plant stress responses [ 164 , 165 ].…”

“…The enhanced expressions of MYB and WRKY TFs were also noticed in the Dietzia natronolimnaea -inoculated wheat plants under salinity stress [ 152 ]. Furthermore, 9 genes in the SA pathway and 6 genes encoding phenylalanine ammonia lyase (PAL), a key enzyme in the phenylpropanoids metabolic pathway, were upregulated with respect to the control plants, resulting the induction of systemic resistance in tobacco host plant [ 163 ]. Malviya et al [ 170 ] also found that the infection of Burkholderia anthina MYSP113 into the sugarcane plantlets cv.…”

“…On the other hand, changes in their transcriptome in response to their colonized plants were also recorded [ 173 ]. During the interaction with the host plant, 2 genes ilvB and PPYC1_23850 related to Aux biosynthesis, 3 genes belonging to cell motility category (e.g., fliG , fliH , fliF ), 31 genes related to transport proteins including 16 genes belong to ATP-binding cassette (ABC), and 3 genes associated with a major facilitator superfamily (MFS) in P. polymyxa YC0136 were significantly upregulated [ 163 ]. It was thought that root exudates from tobacco attracted P. polymyxa YC0136 and may play roles as nutrients source for the growth of YC0136 strain.…”