Identification and expression analysis of miR396 and its target genes in Jerusalem artichoke under temperature stress.

The highly conserved miR396 plays a pivotal role in the growth, development, and responses to abiotic and biotic stresses in plants. However, research on miR396 and its targets in Jerusalem artichoke remains largely unexplored. In this study, we employed bioinformatics and experimental techniques, such as cloning and qRT-PCR, to investigate the regulatory role of miR396 on its targets, leveraging our lab's transcriptomic and degradomic data of Jerusalem artichoke. Specifically, we initially cloned and characterized the precursors (htu-MIR396a/b/c) and mature sequences (htu-miR396a/b/c) of three miR396 isoforms. Subsequently, we identified nine target genes, including seven Growth-Regulating Factors (GRFs) (HtGRF3/4/6/9/10/12/13), one WRKY transcription factor (HtWRKY40), and one Scarecrow-like (SCL) transcription factor (HtSCL33). Finally, we conducted an analysis of their expression patterns across various tissues and their responses to temperature stress. Notably, htu-MIR396s exhibited high expression in seedling stems, while htu-miR396s predominantly expressed in seedling leaves. Moreover, HtWRKY40 and HtSCL33 displayed higher expression levels than HtGRFs in most tissues, except leaves. Remarkably, HtGRF4/6/10/12/13 exhibited higher expression in leaves than in roots and stems during seedling growth. Furthermore, during tuber development, HtGRF4/6/10, HtWRKY40, and HtSCL33 were highly expressed, while HtGRF3/9/12/13 showed relatively lower expression levels. Under heat stress (42℃), htu-MIR396 expression was up-regulated, and htu-miR396 showed dynamic expression patterns in seedlings, resulting in the induction of HtGRF4/6/10/12/13 in leaves and HtSCL33 in roots, while HtWRKY40 in leaves was repressed. Conversely, under cold stress (4℃), htu-MIR396s showed fluctuating expression levels, and htu-miR396s were up-regulated in seedlings. Notably, HtGRF4/13 and HtSCL33 in seedlings were reduced, whereas HtGRF6 in roots and HtWRKY40 in leaves were enhanced. These findings offer valuable insights into the functional roles of miR396-target interactions under abiotic stress in Jerusalem artichoke.

Unveiling HSP40/60/70/90/100 gene families and abiotic stress response in Jerusalem artichoke.

Heat shock proteins (HSPs) are essential for plant growth, development, and stress adaptation. However, their roles in Jerusalem artichoke are largely unexplored. Using bioinformatics, we classified 143 HSP genes into distinct families: HSP40 (82 genes), HSP60 (22 genes), HSP70 (29 genes), HSP90 (6 genes), and HSP100 (4 genes). Our analysis covered their traits, evolution, and structures. Using RNA-seq data, we uncovered unique expression patterns of these HSP genes across growth stages and tissues. Notably, HSP40, HSP60, HSP70, HSP90, and HSP100 families each had specific roles. We also studied how these gene families responded to various stresses, from extreme temperatures to drought and salinity, revealing intricate expression dynamics. Remarkably, HSP40 showed remarkable flexibility, while HSP60, HSP70, HSP90, and HSP100 responded specifically to stress types. Moreover, our analysis unveiled significant correlations between gene pairs under stress, implying cooperative interactions. qRT-PCR validation underscored the significance of particular genes such as HtHSP60-7, HtHSP90-5, HtHSP100-2, and HtHSP100-3 in responding to stress. In summary, our study advances the understanding of how HSP gene families collectively manage stresses in Jerusalem artichoke. This provides insights into specific gene functions and broader plant stress responses.

Salt stress affects the biomass of industrial crop Jerusalem artichoke by affecting sugar transport and metabolism.

Even though Jerusalem artichoke (Helianthus tuberosus L.) has strong resistance to abiotic stresses, salinity can still reduce the biomass of Jerusalem artichoke. The purpose of this study was to elucidate the differences in the development of Jerusalem artichoke and the dynamics of sugar throughout the growth period under high (7.23-8.15 g/kg) and low (3.20-4.32 g/kg) salinity stress in the field in Jiangsu Province, China. This study confirmed that high salinity promoted the conversion of reducing sugars to non-reducing sugars (fructans) in Jerusalem artichoke tubers, but significantly reduced the biomass of Jerusalem artichoke and advanced the peak time of the dry matter accumulation of aerial parts. In addition, in the early and late stages of tuberization, the total sugar content of tubers under low salinity conditions (786 ± 8 mg/g and 491 ± 8 mg/g) was 93.3% and 1.15 times than those under high salinity conditions, respectively. Moreover, the total sugar content in stems was consistently greater under high than low salinity conditions in the same period. The accumulation rate and the amount of dry matter were significantly higher in stems than in other tissues. Therefore, the aerial parts of "Nanyu No. 1" could be harvested before mid-to-early October, and the tubers after mid-November. This study revealed the internal reasons for the decreased yield of Jerusalem artichoke under salt stress, and provided theoretical basis and guidance for the cultivation and utilization of Jerusalem artichoke in saline-alkali soil.

Microbiome structure and function in rhizosphere of Jerusalem artichoke grown in saline land.

The improvement and development of saline-alkali soils is currently a hot economic and scientific issue, and exploring the correlation between rhizosphere microorganisms of plants growing on saline-alkali soils and their salt tolerance has become the key point of related research. In our study, the community structure of microorganism and various properties of saline soils were characterized in which Jerusalem artichoke grown along a soil salinity gradient. A variety of basic soil properties were measured and the amplicon was performed as well as metagenomic sequencing on coastal saline soils using various techniques (such as RDA analysis and the assembly of genomes) to evaluate microbial functions. In addition, WGCNA (Weighted gene coexpression network analysis) method was used to identify the species related to salt stress and the sequence binning to assemble two enriched putative bacterial genomes. The research showed the cultivation of Jerusalem artichoke on saline soil changed soil physico-chemical and enzymatic properties; most of the rapidly changing as well as the long-term stable properties differed significantly between the rhizosphere and bulk soils. The amplicon and metagenomic sequencing revealed the function and structure of microorganisms varied between the rhizosphere and bulk soils, with greater microbial diversity in the rhizosphere. Catalase activity and the moisture content were the factors with the greatest impact on microorganisms. The putative genomes of two species of microorganisms (belong to Nitrospira and Gemmatimonas) were assembled, identified microbial species that were highly responsive to salt stress and that may play a key role in saline soil, stressed the important role of archaea in microbial communities in response to salt stress. The study provides a comprehensive understanding of the microbial community structure in the rhizosphere of Jerusalem artichoke to enable the improvement and economic development of saline land.

The mechanisms of improving coastal saline soils by planting rice.

Planting rice is one of the effective ways to improve saline soils, but the underlying mechanisms are unknown. We studied basic soil properties (including pH, salt content, total nitrogen, etc.) and microbial diversity of the bare soil (salt content >4 g/kg, CK), the Suaeda (Suaeda glauca (Bunge) Bunge) soil (JP), and the soil in which rice (cv. Huaidao 5) grew for one (1Y) and three (3Y) years. The results showed that the soil salinity decreased in the order: CK > JP > 1Y > 3Y. The contents of soil organic matter, total nitrogen, dissolved organic carbon, readily oxidizable carbon, microbial biomass carbon, and particulate organic carbon were higher in 1Y and 3Y compared with CK. The Chao 1 index of soil microbiome diversity was about 1.20 times and 1.49 times higher in the soils after rice compared with JP and CK, respectively. Among the soil microorganisms, the top four abundant phyla were Proteobacteria, Chloroflexi, Bacteriodetes, and Firmicutes. In summary, planting rice decreased soil salinity, and increased the content of nutrients and diversity of microorganisms, thereby improving the saline soil.