Screening of inbred lines to develop a thermotolerant sunflower hybrid using the temperature induction response (TIR) technique: a novel approach by exploiting residual variability

Abstract

Plants, when exposed to sub-lethal stress (induction stress), develop the ability to withstand severe temperatures and this phenomenon is often referred to as acquired thermotolerance. Earlier it was reported that induction stress alters gene expression and brings greater adaptation to heat stress and that the genetic variability in thermotolerance is only seen upon induction stress. Based on this concept, the temperature induction response (TIR) technique has been developed to identify thermotolerant lines. By following the TIR technique, sunflower hybrid KBSH-1 parents were screened for high temperature tolerance. Seedlings of parental lines including CMS 234 A, CMS 234 B and 6 D-1 showed considerable genetic variability for thermotolerance and it was attributed to the expression of existing residual variability for stress responses. Thus, the existing variability forms the basis for identifying thermotolerant lines. The identified parental inbred lines were selected and established in the field and crossed to get F1 hybrid seeds. The KBSH-1 hybrid developed from selected variants of parental lines was compared with the original KBSH-1 for thermotolerance. The selected KBSH-1 was more tolerant compared with the original hybrid both at the seedling as well as at the plant level. The physiological and molecular basis of thermotolerance was studied in the KBSH-1 original and the hybrid developed from selected variants of parental lines. The selected hybrid exhibited high tolerance to Menadione (naphthoquinone)-induced oxidative stress. Even the methyl viologen-induced oxidative stress damage was relatively less in the selected hybrid population. The selected hybrid also showed enhanced expression of the heat shock proteins HSP 90 and HSP 104 and also accumulated higher levels of the heat shock transcription factor HSFA.

Improving Photosynthetic Responses during Recovery from Heat Treatments with Brassinosteroid and Calcium Chloride in Indian Bread Wheat Cultivars

“…Earlier reports [31] [41] [42] have suggested the identification of tolerance level in different genotypes following exposure to a sub-lethal induction stress. This can chiefly be attributed to the changing transcriptome upon exposure to thermal stress [42] [43].…”

“…Seeds showing germination were subjected to lethal temperature stress of 51˚C for 3 h with prior induction at sublethal temperature of 37˚C for 1.5 h. Immediately after the treatment, seedlings were allowed to recover at 22˚C ± 1˚C. On the 10 th day, from the date of imbibition of seeds, the percentage survival of seeds were scored [31].…”

AtCYP710A1gene-mediated stigmasterol production plays a role in imparting temperature stress tolerance inArabidopsis thaliana

“…Acclimation-based temperature stress imposition was performed according to previous literature. 14 The survival percentage of the Atcyp710a1 mutant was lower than the wild-type during both acclimated and nonacclimated high temperature stress. AtCYP710A1 overexpressor plants, either acclimated with mild temperature stress or nonacclimated, showed a significant increase in survival percentage after exposure to severe temperatures of 45°C for 6 h ( Fig.…”

“…12 Therefore, cell membrane stability assays are commonly used to assess the tolerance of plants to various abiotic stresses. 13,14 Stability of plasma membrane and other organellar membranes during abiotic stress contributes to the maintenance of cellular metabolic activity. 15 In addition, stability of chlorophyll during stress allows cells to maintain a functional chloroplast so that photosynthesis can be revived after the plant's recovery from stress.…”

Functional characterization of Nicotiana benthamiana homologs of peanut water deficit-induced genes by virus-induced gene silencing

“…Relevance of HSP70 in thermotolerance (Lee and Schoffl 1996;Senthil-Kumar et al 2003) and its role in regulating various heat shock transcription factors (HSFs) to bring in coordinated expression of several HSPs for adaptation has been elucidated in several studies (Kim and Schoffl 2002). The HSP70 silenced plants showed reduced growth rate and deviant leaf morphology even under non-stress conditions.…”