Phylogenetic analysis and expression profiles of jasmonate ZIM-domain gene family provide insight into abiotic stress resistance in sunflower.

Jasmonate ZIM-domain (JAZ) proteins act as inhibitory factors of the jasmonic acid (JA) pathway, which is involved in regulating plant development and defense responses. However, there are no extensive studies available on JAZ genes in sunflower (Helianthus annuus L.). In this study, the phylogenetic analysis of 139 putative JAZ genes from eight plants demonstrated that these JAZs could be divided into five groups (Groups I-V), and the 27 sunflower JAZs (HaJAZs) were classified into these five groups. All groups contained genes from both monocotyledons and dicotyledons, indicating that the emergence of JAZ genes predates the differentiation of monocotyledons and dicotyledons. Both segmental and tandem duplications contributed greatly to this gene family's expansion in sunflower, especially in Group II. Moreover, the expression profiles of HaJAZ genes under normal conditions, hormone treatments or abiotic stresses were analyzed based on RNA-seq data. HaJAZ2 may be undergoing pseudogenization as a nonfunctional gene because it was not expressed in any tissue. Many HaJAZ genes in roots upregulated their expression when involved in responding to exogenous hormones, especially methyl-jasmonate. The abiotic stress treatments of sunflower showed that HaJAZ5, HaJAZ15, HaJAZ17, HaJAZ20, and HaJAZ21 tend to be sensitive to certain abiotic stresses. HaJAZs from different groups may share similar functions but also exercise their unique functions when responding to abiotic stresses. We speculated that this gene family was conserved in sequence but varied in its expression among duplicated HaJAZ genes, which implies that they may confer neofunctionalization in the adaptation to abiotic stresses; this work provides insight into the resistance of sunflowers and their adaptation to diverse environmental conditions.

Diversity patterns of soil microbial communities in the Sophora flavescens rhizosphere in response to continuous monocropping.

BACKGROUND: Continuous monocropping can affect the physicochemical and biological characteristics of cultivated soil. Sophora flavescens is a valuable herbal medicine and sensitive to continuous monocropping. Currently, diversity patterns of soil microbial communities in soil continuous monocropping with S. flavescens have not been extensively elucidated. RESULTS: In this study, comparative 16S rDNA and internal transcribed spacer (ITS) MiSeq sequencing analyses were used to examine the taxonomic community structure and microbial diversity in nonrhizosphere soil (CK) and rhizosphere soils (SCC, TCC, and FCC) sampled from fields that had undergone two, three, and five years of continuous monocropping, respectively. Among the microbial communities, a decreased abundance of Acidobacteria and increased abundances of Proteobacteria and Bacteroidetes were found with the increase in monocropping years of S. flavescens. As the continuous monocropping time increased, the diversity of the bacterial community decreased, but that of fungi increased. Redundancy analysis also showed that among the properties of the rhizosphere soil, the available phosphorus, organic matter, total nitrogen, and sucrase had the greatest impacts on the diversity of the rhizosphere microbial community. Moreover, a biomarker for S. flavescens soil was also identified using the most differentially abundant bacteria and fungi in soil samples. CONCLUSIONS: Our study indicates that long-term monocropping exerted great impacts on microbial community distributions and soil physicochemical properties. The relationship between microbial community and physicochemical properties of rhizosphere soil would help clarify the side effects of continuous S. flavescens monocropping. Our study may aid in uncovering the theoretical basis underlying obstacles to continuous monocropping and provide better guidance for crop production.

Effect of cultivating Pleurotus ostreatus on substrates supplemented with herb residues on yield characteristics, substrates degradation, and fruiting bodies' properties.

BACKGROUND: Inappropriate disposal of herb residues in China has caused major problems for the immediate environment and to human safety. Here, three herb residues, compound Kushen injection (CKI), Qizhi Tongluo capsule (QTC), and Shenbai Shuxin capsule (SSC), were applied as substrates to corncob at various ratios (30:60, 45:45, and 60:30) for the propagation of the mushroom Pleurotus ostreatus. The effects of supplementation using herb residues on yield, biodegradation ability, bioactive compounds, antioxidant properties, and safety of P. ostreatus were assessed. RESULTS: Different spawn running times were observed using growth medium, whereas 45CKI, 60QTC, and 30SSC media were determined as optimal-performing substrate combinations, resulting in yields of 843 g kg-1 , 828 g kg-1 , and 715 g kg-1 respectively. Biodegradation analysis of consumed substrates revealed a significant decrease in cellulose and hemicellulose levels compared with lignin. Furthermore, chemical analysis of fruiting bodies revealed that the 45CKI and 60QTC substrates resulted in higher total phenol, flavonoid, terpenoid, and vitamin C levels, but significantly reduced water-soluble polysaccharides compared with the corncob medium. The methanol extract of fruiting bodies grown on substrates containing herb residues exhibited higher antioxidant properties than the control, as it was more effective in scavenging 2,2-diphenyl-1-picrylhydrazyl radicals, had greater reducing power, and more strongly inhibiting lipid peroxidation. Furthermore, high-performance liquid chromatography studies indicated that fruiting bodies did not generate matrine (a specific toxin produced in Kushen) when cultivated using the CKI substrate. CONCLUSIONS: P. ostreatus cultivation on substrates mixed with herb residues facilitates herb residue management as well as bioactivity-rich and non-toxic fruit body formation. © 2020 Society of Chemical Industry.