Transcriptome differences between fiber-type and seed-type Cannabis sativa variety exposed to salinity

Abstract

The industrial hemp varieties 'Yunma 5' and 'Bamahuoma,' which demonstrate growth vigor and environmental adaptability, have been primarily cultivated in Yunnan and Guangxi, China, respectively, for fiber and seeds. The results of physiological measurements showed the phenotypic differences between the two varieties in response to salt stress. RNA-Seq analysis was first performed on leaves of both varieties sampled at four time intervals (0, 2, 4, 6 days) after treatment with salt (500 mM NaCl) We identified 220 co-up-regulated differentially expressed genes (DEGs) in the two varieties, while 26 upregulated DEGs and 24 down-regulated DEGs were identified exclusively in the single varieties after 2 days of salt stress. Among the 220 DEGs, we identified 22 transcription factors, including key transcription factors involved in salt stress, such as MYB, NAC, GATA, and HSF. We applied gene expression profile analysis and found that 'Yunma 5' and 'Bamahuoma' have variety-specific pathways for resisting salt stress. The DEGs of 'Yunma 5' were enriched in spliceosome and amino acid metabolism genes, while the DEGs of 'Bamahuoma' were enriched in fatty acid metabolism, amino acid metabolism, and endoplasmic reticulum protein processing pathway. Although there were common DEGs, such as genes encoding cysteine protease and alpha/beta-hydrolase superfamily, the two varieties' responses to salt stress impacted different metabolic pathways. The DEGs that were co-expressed in both varieties under stress may provide useful insights into the tolerance of cultivated hemp and other bast fiber crops to saline soil conditions. These transcriptomes also represent reference sequences for industrial hemp.

Textile Hemp vs. Salinity: Insights from a Targeted Gene Expression Analysis

“…It should, however, be noted that, despite the high NaCl concentration used, no visible signs of shock in the aerial parts of hemp plantlets could be noticed after the first application; while we cannot exclude the short-term (within hours) differential regulation of genes related to the osmotic component of salt shock, the aerial tissues appeared, phenotypically, as turgid as control plants, and no discernible discoloration could be noticed, either. Hemp is known to be a robust crop vs. exogenous constraints; nevertheless, different varieties showing varying susceptibility to salinity have already been studied in the literature [ 18 ]. Although further analyses are necessary to fully understand the susceptibility to salinity of the cultivar here studied, i.e., Santhica 27, we can claim that noticeable effects (growth arrest, loss of turgidity in the leaves) started to be clear only after 2 weeks of treatment.…”

“…The primer sequences, amplification efficiencies and R 2 have either been previously published ( eTIF4E , TIP41 , F-BOX , RAN , PAL , CAD , 4CL , FLA1 - 3 - 6 - 8 - 10 , EXPA8 , CesA4 - 7 - 8 [ 19 , 23 ]), or are indicated in Table 1 . The identification numbers (IDs) of the genes actin depolymerizing factor 5 ADF5 , ethylene response factor ERF1 , auxin-responsive protein IAA11 , calcium-dependent lipid-binding family protein isoform 2 CALB2 , calcium-dependent lipid-binding family protein isoforms 4 CALB4-1 , -2 , -3 , heat shock protein 70 HSP70-1 and -2 , heat shock protein HSP81.4 , and gibberellin receptor 1b GIBB-REC , histidine kinase 4-like HK4 have been previously described [ 18 ].…”

“…For example, in flax, NaCl exposure (50 mM NaCl) triggered the increased expression (log 2 FC as compared to control >6.8) of a NAC47 gene, together with a β-glucosidase 17, a dehydrin and a cytochrome CYP82C4 [ 17 ]. More recently, the response to salinity (500 mM NaCl) was compared in the leaves of a seed vs. textile hemp variety using RNA sequencing (RNA-Seq) [ 18 ]: this study demonstrated that the fiber variety, after salt stress, showed an enrichment in genes belonging to the spliceosome ontology and amino acid metabolism, while in the seed variety there was a predominance of genes related to fatty acid and amino acid metabolisms, as well as endoplasmic reticulum protein processing pathway. In the same work, 220 co-upregulated differentially expressed genes were identified, among which several transcription factors belonging to the MYB, NAC, GATA and HSF families.…”

Aquaponic and Hydroponic Solutions Modulate NaCl-Induced Stress in Drug-Type Cannabis sativa L.

“…C. sativa is an annual herbaceous crop of increasing economic importance for a multitude of uses: hemp-type cultivars are a significant source of bast and woody fibers and drug-type cultivars produce a trove of secondary metabolites (namely Δ 9 -tetrahydrocannabinolic acid ~ THCA and cannabidiolic acid ~ CBDA) which are of significant medicinal value ( Gonçalves et al, 2019 ). Hemp-type cultivars of C. sativa [those which produce < 0.3% THC according to Small et al (1975) ] demonstrate several mechanisms to enhance tolerance to NaCl ( Liu et al, 2016 ; Guerriero et al, 2017 ). Hemp has shown some ability to tolerate NaCl in trials involving seed germination (> 70% germinating in 150 mM NaCl) ( Hu et al, 2018 ) and seedling development (4.4% greater chlorophyll content at 100 mM NaCl compared to the control) ( Hu et al, 2019 ).…”

“…Given the decrease in physiological parameters for plants grown in hydroponic solution, it is suggested that such mechanisms observed in hemp may not occur to the same extent in drug-type cultivars; however, further research is needed to quantify the production of radicals and stress related proteins to verify this. Furthermore, future research should involve multiple cultivars, to clarify if drug-type C. sativa cultivars have a cultivar-dependent response to NaCl as prominently shown in hemp-type cultivars (Liu et al, 2016).…”