Karumanchi Appa Rao, Sivan Pramod, Kummari Divya, Rajasheker G, Kumar S Anil, Reddy Palakolanu Sudhakar, Suravajhala Prashanth, Podha Sudhakar, Kishor P B Kavi
Department of Biotechnology, Acharya Nagarjuna University, Nagarjuna Nagar, Guntur 522 209, India.
Department of Chemistry, Division of Glycoscience, KTH Royal Institute of Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, Albanova University Center, SE-10691 Stockholm, Sweden.
Plants (Basel). 2023 Jun 21;12(13):2400. doi: 10.3390/plants12132400.
Roots from salt-susceptible ICSR-56 (SS) sorghum plants display metaxylem elements with thin cell walls and large diameter. On the other hand, roots with thick, lignified cell walls in the hypodermis and endodermis were noticed in salt-tolerant CSV-15 (ST) sorghum plants. The secondary wall thickness and number of lignified cells in the hypodermis have increased with the treatment of sodium chloride stress to the plants (STN). Lignin distribution in the secondary cell wall of sclerenchymatous cells beneath the lower epidermis was higher in ST leaves compared to the SS genotype. Casparian thickenings with homogenous lignin distribution were observed in STN roots, but inhomogeneous distribution was evident in SS seedlings treated with sodium chloride (SSN). Higher accumulation of K and lower Na levels were noticed in ST compared to the SS genotype. To identify the differentially expressed genes among SS and ST genotypes, transcriptomic analysis was carried out. Both the genotypes were exposed to 200 mM sodium chloride stress for 24 h and used for analysis. We obtained 70 and 162 differentially expressed genes (DEGs) exclusive to SS and SSN and 112 and 26 DEGs exclusive to ST and STN, respectively. Kyoto Encyclopaedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis unlocked the changes in metabolic pathways in response to salt stress. qRT-PCR was performed to validate 20 DEGs in each SSN and STN sample, which confirms the transcriptomic results. These results surmise that anatomical changes and higher K/Na ratios are essential for mitigating salt stress in sorghum apart from the genes that are differentially up- and downregulated in contrasting genotypes.
盐敏感型ICSR - 56（SS）高粱植株的根系中，后生木质部细胞的细胞壁薄且直径大。另一方面，在耐盐型CSV - 15（ST）高粱植株中，其根的皮层和内皮层具有厚且木质化的细胞壁。对植株施加氯化钠胁迫处理（STN）后，皮层中次生壁厚度和木质化细胞数量增加。与SS基因型相比，ST叶片下表皮下方厚壁细胞次生壁中的木质素分布更高。在STN根中观察到凯氏带增厚且木质素分布均匀，但在经氯化钠处理的SS幼苗（SSN）中，木质素分布不均匀。与SS基因型相比，ST中钾的积累量更高，钠含量更低。为了鉴定SS和ST基因型之间差异表达的基因，进行了转录组分析。两种基因型均暴露于200 mM氯化钠胁迫下24小时后用于分析。我们分别获得了SS和SSN特有的70个和162个差异表达基因（DEG），以及ST和STN特有的112个和26个DEG。京都基因与基因组百科全书（KEGG）和基因本体论（GO）富集分析揭示了盐胁迫响应中代谢途径的变化。对每个SSN和STN样本中的20个DEG进行qRT - PCR验证，证实了转录组结果。这些结果推测除了在不同基因型中差异上调和下调的基因外，解剖学变化和更高的钾/钠比对于减轻高粱的盐胁迫至关重要。
