Biotic and Abiotic stress
Navid Taherifar; Hengameh Taheri
Abstract
Heat stress has detrimental effects on the growth and performance of plants through biochemical, physiological, morphological, and molecular changes. Plants have developed complex mechanisms to balance growth and tolerance to stress, allowing them to effectively defend against more severe stresses by ...
Read More
Heat stress has detrimental effects on the growth and performance of plants through biochemical, physiological, morphological, and molecular changes. Plants have developed complex mechanisms to balance growth and tolerance to stress, allowing them to effectively defend against more severe stresses by remembering mild stress and forming heat stress memory, known as thermopriming. To investigate the role of thermopriming in inducing the transcription response of HSFA2, HSFA1b and MIPS2 genes, the changes in the transcriptional level of the genes were studied at different times after priming and return stress in canola seedlings using the qRT-PCR technique. The results showed that the expression of these genes was not stable during the recovery period after the initial mild stress (memory phase), while their transcription level immediately after facing the second severe stress was induced at a much higher level in primed plants (P+T treatment) compared to non-primed plants (T treatment) which continued until 48 hours after return stress. Also, morphological analysis of seedlings at 7 and 14 days after release from the second stress showed that thermopriming increase the growth indices and heat tolerance in these plants through strengthening the expression of stress memory genes. Since the HSFA1b, HSFA2 and MIPS2 genes have maintained their expression level until days after the return stress, these genes can be the key components of the transcriptional memory of heat stress and be used in breeding programs and the development of heat tolerant varieties.
Bioinformatics
Atena AlKian Abadi; Hengameh Taheri; Ayeh Sadat Sadr
Abstract
Plants are able to acquire thermotolerance to the subsequent lethal stress through memorizing previous heat stress (HS) (Priming). A priming effect that can be sustained for several hours, days, or even generations after reverse heat stress, is called heat stress memory. The aim of this study was to ...
Read More
Plants are able to acquire thermotolerance to the subsequent lethal stress through memorizing previous heat stress (HS) (Priming). A priming effect that can be sustained for several hours, days, or even generations after reverse heat stress, is called heat stress memory. The aim of this study was to identify effective key genes in establishing and maintaining heat stess memory. To achieve this, microarray data of the expression profile of Arabidopsis samples were retrieved from the GEO (Gene expression omnibus) database and differentially expressed genes (DEGs) were identified based on their higher transcriptional activation following recurring stress (in P+T/P treatment comparison) and their sustained induction even 52 hours after stress relief (during memory phase).The identified genes were further analyzed by bioinformatics tools for gene ontology (GO) classification and protein-protein interaction (PPI) networks. GO terms analysis disclosed that the up-regulated DEGs were mainly associated with cellular response to heat, heat acclimation and protein folding. By clustering of PPI networks in the term related to response to heat (in P+T/P treatment comparison), several candidate genes involved in thermomemory were identified including HSP70T-2, HSP91, AR192, HSP60, HSP70, BIP2, J2, CLPB4, HOP3, HSP101, ROF1, HSFA3, HSFA2, HSP70B, CLPB3, FES1A, MBF1C. Also, based on the sustained differential expression of genes even 52 hours after the priming phase, it was determined that genes responsible for maintaining heat stress memory were mainly members of the small heat shock protein family (sHSPs) such as HSP17.6, HSP21, HSP17.6II, HAS32, HSP17.4, HSP18.2 and HSP22. KEGG (Kyoto Encyclopedia of Genes and Genome) pathway analysis revealed that the HS memory genes were mainly involved in protein processing in the endoplasmic reticulum (ER) and oxidative phosphorylation. Furthermore, the analysis of cis-regulatory elements in the promoter regions of the thermomemory genes revealed that the transcription factors families of bZIP, AP2;B3;RAV, MYB/SANT, HD-ZIP and GATA; tify had the highest binding sites in their upstream regions. In summary, these findings provide useful information about functional and regulatory analysis of genes involved in the establishment and maintenance of heat stress memory, as well as their protein network interactions. This information can be used to improve the heat tolerance capacity of plants under extreme heat stress.
