Strigolactones positively regulate Verticillium wilt resistance in cotton via crosstalk with other hormones

Abstract

Verticillium wilt caused by Verticillium dahliae is a serious vascular disease in cotton (Gossypium spp.). V. dahliae induces the expression of the CAROTENOID CLEAVAGE DIOXYGENASE 7 (GauCCD7) gene involved in strigolactone (SL) biosynthesis in Gossypium australe, suggesting a role for SLs in Verticillium wilt resistance. We found that the SL analog rac-GR24 enhanced while the SL biosynthesis inhibitor TIS108 decreased cotton resistance to Verticillium wilt. Knock-down of GbCCD7 and GbCCD8b genes in island cotton (Gossypium barbadense) decreased resistance, whereas overexpression of GbCCD8b in upland cotton (Gossypium hirsutum) increased resistance to Verticillium wilt. Additionally, Arabidopsis (Arabidopsis thaliana) SL mutants defective in CCD7 and CCD8 putative orthologs were susceptible, whereas both Arabidopsis GbCCD7- and GbCCD8b-overexpressing plants were more resistant to Verticillium wilt than wild-type (WT) plants. Transcriptome analyses showed that several genes related to the jasmonic acid (JA)- and abscisic acid (ABA)-signaling pathways, such as MYELOCYTOMATOSIS 2 (GbMYC2) and ABA-INSENSITIVE 5, respectively, were up-regulated in the roots of WT cotton plants in responses to rac-GR24 and V. dahliae infection but down-regulated in the roots of both GbCCD7- and GbCCD8b-silenced cotton plants. Furthermore, GbMYC2 suppressed the expression of GbCCD7 and GbCCD8b by binding to their promoters, which might regulate the homeostasis of SLs in cotton through a negative feedback loop. We also found that GbCCD7- and GbCCD8b-silenced cotton plants were impaired in V. dahliae-induced reactive oxygen species (ROS) accumulation. Taken together, our results suggest that SLs positively regulate cotton resistance to Verticillium wilt through crosstalk with the JA and ABA-signaling pathways and by inducing ROS accumulation.

Identification and expression of strigolactone biosynthesis and signaling genes and the in vitro effects of strigolactones in olive (Olea europaea L.)

“…This suggests that SL promoter elements in olives might play a role in light response. Additionally, previous research has indicated crosstalk between SLs and other hormones in shoot branching (Foo et al, 2005;Ito et al, 2017;Liu et al, 2015;Yi et al, 2023;Yu et al, 2021). For instance, SLs act as positive regulators in disease response in cotton through hormonal crosstalk (Yi et al, 2023).…”

“…Additionally, previous research has indicated crosstalk between SLs and other hormones in shoot branching (Foo et al, 2005;Ito et al, 2017;Liu et al, 2015;Yi et al, 2023;Yu et al, 2021). For instance, SLs act as positive regulators in disease response in cotton through hormonal crosstalk (Yi et al, 2023). Transcript levels of SL biosynthesis and signaling genes can be modulated by auxin, abscisic acid, or gibberellin (Foo et al, 2005;Ito et al, 2017;Liu et al, 2015), and SLs interact with auxin at the protein level in tomato (Yu et al, 2021).…”

The Overexpression of Zea mays Strigolactone Receptor Gene D14 Enhances Drought Resistance in Arabidopsis thaliana L.

“…In island cotton (Gossypium barbadense L.), the knockout of these genes results in diminished disease resistance. Conversely, in upland cotton (Gossypium hirsutum L.), the overexpression of the GbCCD8b gene correlates with an increase in disease resistance [67]. In the medium supplemented with GR24, many plant root pathogens showed growth inhibition, including Fusarium solani f. sp.…”

Interactions between Verticillium dahliae and cotton: pathogenic mechanism and cotton resistance mechanism to Verticillium wilt

“…The carotenoid cleavage dioxygenases GbCCD7 and GbCCD8b positively regulated the accumulation of strigolactone and consequently activated the JA and ABA signaling. The positive feedback loop of ABA and the negative feedback loop of JA could regulate the homeostasis of strigolactone and maintain the balance among these three hormones, thereby improving the tolerance of cotton to Verticillium wilt (Yi et al, 2023).…”