GhAOS integrates circadian rhythm and jasmonic acid signaling to regulate high temperature stress responses in cotton and Arabidopsis

Abstract

Background: Cotton (Gossypium spp.) cultivation is significantly challenged by high temperatures (HT), especially during reproductive stages, leading to male abortion and yield losses.

Results: This study investigated the complex interplay between circadian rhythm (CR), HT, and jasmonic acid (JA) signaling in cotton and Arabidopsis. Disruption of CR led to reduced JA content, triggering bud yellowing and abscission at the tetrad stage (TS) in the HT-sensitive cotton line H05 and longer stigma in Arabidopsis. To elucidate the role of JA under continuous light (CL), targeting the JA biosynthesis gene GhAOS in cotton and using Arabidopsis mutants aos and aoc2 revealed accelerated drying, decreased JA content, and male sterility, alongside altered expression patterns of pivotal bioclock-associated genes (PRR1 and LHY). Additionally, mutant anthers manifested elevated ion leakage and H₂O₂ levels, coupled with reduced activities of antioxidant enzymes SOD and POD during CL + HT stress.

Conclusions: Current study investigated the complex interplay between CR, HT, and JA signaling pathways in cotton and Arabidopsis, focusing on their impact on male fertility under HT stress. These findings highlight the importance of JA and CR in plant fitness, crucial for future crop improvement and sustainable agriculture.

Keywords: Gossypium hirsutum; Circadian rhythm; High temperature stress; Jasmonic acid signaling.

Fig. 1

Effect of continuous light (CL) stress on cotton and Arabidopsis buds. A, B Phenotype comparisons of WT cotton plants under normal conditions (A) and CL stress (B). The buds including TS anthers of WT cotton plants under CL stress were yellow in colour (B) compared to those under normal conditions. C, D Represent the qRT-PCR results of PSEUDO RESPONSE REGULATOR1 (APRR1) and Late Elongated Hypocotyl (LHY) genes in cotton anthers (n = 4, Additional file 8: Data set S1) at TS stage under normal (C) and CL stress (D) conditions. E Represent the quantification of JA and JA-Ile in cotton anthers (n = 3, Additional file 8: Data set S1) at TS stage under normal and CL stress condition. F, G Phenotype comparisons of WT Arabidopsis plants under normal conditions (F) and CL stress (G). The stigma is found longer in size in the buds of CL treated plants (G) compared to those under normal conditions (F). H, I Represent the qRT-PCR expression of Timing of CAB Expression1 (TOC1) and LHY genes in Arabidopsis anthers (n = 3, Additional file 8: Data set S1) under normal (H) and CL stress condition (I). J Represent the quantification of JA and JA-Ile in Arabidopsis anthers (n = 3, Additional file 8: Data set S1) under normal and CL stress condition. Scale: The white Lines represent 4 cm (F, G), 5 cm (A, B), and red Line represent 1 mm. Samples were collected every 4 h following the initiation of experimental treatment at 04:00 pm (C, D, H, I). WT wild type, CL continuous light, TS tetrad stage

Fig. 2

Comparison of phenotypes under normal and CL + HT conditions with WT, Ghaos-mutant line in flower, anthers and pollen grains. A–H Phenotype comparison of WT (A) and Ghaos mutant plants (E) in flowers (B, F), anthers (C, G), and pollen grains (D, H) under normal conditions. In Ghaos mutant plant, flower size was reduced (F), anthers were dehiscent (G) and pollen grains were sterile (H) as compared to WT plants. I–P) Phenotype comparison of WT (I) and Ghaos mutant plant (M) in flowers (J, N), anthers (K, O), and pollen grains (L, P) under CL + HT conditions. In Ghaos mutant plant (M), leaves start yellowing (M), the buds as well as bolls start falling (M). Moreover, the flower size reduced (N), anthers were indehiscent and change to red color (O), and pollen grains were sterile and aberrant in shape (P). Q–R Graph representing the number of cotton bud’s percentage (Q) and number of pollen grains percentage (R) in normal and aos-mutant plants (n = 5, Additional file 9: Data set S2) under CL + HT stress. Scale: The white Line represents 1 cm (B, C, F, G, J, K, N, O) And 5 cm (A, E, I, M), red Line represents 100 µm (D, H, L, P). WT wild type, CL continuous light stress, aos allene oxide synthase

Fig. 3

Comparison of WT, Ghaos, and Ghaoc-mutant Arabidopsis plants under normal and CL + HT conditions. A–C Phenotype comparison of WT, Ghaoc, and Ghaos mutant plants after 0 days (A), 3 days (B), And 4 days (C) under normal conditions. D–F Phenotype comparison of WT, Ghaoc, and Ghaos mutant plants after 0 days (D), 3 days (E), And 4 days (F) under CL + HT conditions. G–L Enlarged view the rosette leaf phenotype of WT (G, J), Ghaoc (H, K), and Ghaos (I, L) mutant plants after 4 days in (C and F) under normal and CL + HT conditions, respectively. M, N Graph representing the number of Arabidopsis leaves (n = 10) (M) and number of fertile flowers (n = 10) (N) under CL + HT stress. Scale: The white Lines represent 4 cm in A–F. Red arrows show withered leaves (K, L). WT wild type, CL continuous light, aos allene oxide synthase, aoc allene oxide cyclase

Fig. 4

Comparison of WT, Ghaos and Ghaoc-mutant flowers And Anthers at 24 h under normal and CL + HT conditions. (A–A10) Comparison of WT (A–L), Ghaoc (M–X), and Ghaos (Y–A10) mutant flowers And Anthers at 24 h under normal and CL + HT stress conditions. To examine the flowers and anthers, Zeiss Axio scope A1 microscope was used for imaging. Scale: The red Line represents 1 mm (A–A10). Red box shows enlarge image of anthers. WT wild type, CL continuous light stress, aos allene oxide synthase, aoc allene oxide cyclase, HT high temperature

Fig. 5

Quantification of JA in Cotton and Arabidopsis anthers and expression profile of JAZ genes in cotton anthers under normal and CL + HT stress condition. A Represent the quantification of JA in WT and Ghaos mutant tetrad stage anthers (n = 3, Additional file 10: Data set S3) at 24 h under normal and CL + HT stress conditions in cotton. B Represent the quantification of JA in WT, Ghaos, and Ghaoc-mutant anthers (n = 3, Additional file 10: Data set S3) at 24 h under normal and CL + HT stress conditions in Arabidopsis. C–F Represent the expression profile of JAZ genes in cotton anthers (n = 3, Additional file 10: Data set S3) under normal and CL + HT stress conditions. Significant differences were found by using one-way ANOVA (P < 0.05). Samples were collected every 4 h following the initiation of experimental treatment at 04:00 pm (A–F). JAZ jasmonate-zim domain, WT wild type, CL continuous light, aos allene oxide synthase, aoc alleneoxide cyclase, JA jasmonic acid

Fig. 6

Measurement of H₂O₂content, POD and SOD activity, and ion leakage in cotton and Arabidopsis anthers. A–CRepresent the H₂O₂content (A), POD (B), and SOD activity (C) in cotton WT and Ghaos mutant tetrad stage anthers (n = 3, R3, Additional file 11: Data set S4) at 24 h under normal and CL + HT stress conditions. D–FRepresent the H₂O₂ content (D), POD (E), and SOD activity (F) in Arabidopsis WT, Ghaos, and Ghaoc mutant tetrad stage anthers (n = 2, R3, Additional file 11: Data set S4) at 24 h under normal and CL + HT stress conditions. G and HIon leakage measurement in WT and Ghaos mutant tetrad stage anthers (n = 2, Additional file 11: Data set S4) at 24 h under normal and CL + HT stress conditions in cotton (G) and in Arabidopsis (H). Error bars represent the standard deviation of three replicates. Significant differences were found by using one-way ANOVA (P < 0.05). Samples were collected every 4 h’ following the initiation of experimental treatment at 04:00 pm (A–H). WT wild type, CL continuous light, aos Allene oxide synthase, aoc Allene oxide cyclase, H₂O₂ hydrogen peroxide, POD peroxiredoxin, SOD superoxide dismutase