Comparative study of rhizobacterial communities in pepper greenhouses and examination of the effects of salt accumulation under different cropping systems

Abstract

This study compared rhizobacterial communities in pepper greenhouses under a paddy-upland (rice-pepper) rotational system (PURS) and a monoculture repeated cropping system (RCS) and examined adverse effects of high salinity on soil properties. The following soil properties were analyzed: electrical conductivity (EC), pH, concentration of four cations (Na, Ca, Mg, and K), total nitrogen, and organic matter content. Rhizobacterial communities were analyzed using culture-based and culture-independent (pyrosequencing) methods. In addition, all culturable bacteria isolated from each soil sample were tested for traits related to plant growth promotion. The EC of rhizospheric soils was 5.32-5.54 dS/m for the RCS and 2.05-2.19 dS/m for the PURS. The culture-based method indicated that the bacterial communities and bacterial characteristics were significantly more diverse in the PURS soil than in the RCS soil. The pyrosequencing data also indicated that the richness and diversity of bacterial communities were greater in the PURS soil. Proteobacteria was the most abundant phylum in soil samples under both cropping systems. However, Firmicutes and Gemmatimonadetes were more prevalent in the RCS soil, while the PURS soil contained a greater number of Chloroflexi. Spearman's correlation coefficients showed that soil EC was significantly positively correlated with the abundance of Firmicutes and Gemmatimonadetes and negatively correlated with the abundance of Acidobacteria, Chloroflexi, and Deltaproteobacteria. This is the first study on the rhizobacterial communities in pepper greenhouses under two different cropping systems using both culture- and pyrosequencing-based methods.

Effects of Soil Nutrients, Enzyme Activities and Microbial Composition in Vegetable-Polygonatum Odoratum Rotation Regimes

“…The studies illustrated that highly diverse cropping systems were less affected by soil-borne pathogens than the plant mono-fields or low-diversity fields. This is consistent with the results of crop diseases (Figure 3), and highlighted that FC system not only increased soil bacterial relative abundance but also decreased soil borne pathogens [25][26][27][28].…”

“…To further understanding the correlation of microbial diversity and environmental factors such as the content of N, P, K, and the activities of PPO, SC, UE and CAT, the Spearman correlation analysis was carried out as reported previously [25]. https://doi.org /10.37358/Rev.…”

Phytobeneficial bacteria improve saline stress tolerance in Vicia faba and modulate microbial interaction network

“…Enterobacteriaceae seem to have shifted from the RAS to the roots in the presence of saline stress. Similar results on the effects of NaCl in the rhizosphere of various agricultural crops (Li et al, 2016;Nie et al, 2016;Hahm et al, 2017;Ibekwe et al, 2017) and on natural halophytes (Liu et al, 2016;Yang et al, 2016) have been previously reported. However, the length of 16S sequences obtained with current high-throughput sequencing techniques is relatively short, and does not allow us to describe OTUs at the species level, and since within the same bacterial genus, phytobeneficial bacteria and pthytopathogens can co-exist, we can hardly claim that the plant, under certain stress conditions, will select specifically beneficial microbiota.…”

Alleviation of Salt Stress in Pepper (Capsicum annum L.) Plants by Plant Growth-Promoting Rhizobacteria

“…Three PGPR strains that possess plant growth-promoting attributes, like phosphate solubilization and the production of IAA, siderophore, and ACC deaminase, were previously isolated from the from the rhizospheric soil of pepper plants growing under saline conditions in Mir-Yang, Republic of Korea [18]. Cultures of the three PGPR strains were grown in 500 ml of tryptic soy broth at 30°C.…”

“…In the present study, we used three PGPR strains that were previously isolated from the rhizosphere of pepper plants grown under highly saline conditions [18]. These isolates were M. oleivorans KNUC7074, B. iodinum KNUC7183, and R. massiliae KNUC7586.…”