Investigating the Association between Flowering Time and Defense in the Arabidopsis thaliana-Fusarium oxysporum Interaction

Abstract

Plants respond to pathogens either by investing more resources into immunity which is costly to development, or by accelerating reproductive processes such as flowering time to ensure reproduction occurs before the plant succumbs to disease. In this study we explored the link between flowering time and pathogen defense using the interaction between Arabidopsis thaliana and the root infecting fungal pathogen Fusarium oxysporum. We report that F. oxysporum infection accelerates flowering time and regulates transcription of a number of floral integrator genes, including FLOWERING LOCUS C (FLC), FLOWERING LOCUS T (FT) and GIGANTEA (GI). Furthermore, we observed a positive correlation between late flowering and resistance to F. oxysporum in A. thaliana natural ecotypes. Late-flowering gi and autonomous pathway mutants also exhibited enhanced resistance to F. oxysporum, supporting the association between flowering time and defense. However, epistasis analysis showed that accelerating flowering time by deletion of FLC in fve-3 or fpa-7 mutants did not alter disease resistance, suggesting that the effect of autonomous pathway on disease resistance occurs independently from flowering time. Indeed, RNA-seq analyses suggest that fve-3 mediated resistance to F. oxysporum is most likely a result of altered defense-associated gene transcription. Together, our results indicate that the association between flowering time and pathogen defense is complex and can involve both pleiotropic and direct effects.

QTL sequencing strategy to map genomic regions associated with resistance to ascochyta blight in chickpea

“…The interaction between flowering and resistance to diseases has been observed in multiple plants. The late‐flowering mutants of Arabidopsis show enhanced resistance to a hemibiotrophic pathogen Fusarium oxysporum , suggesting the relationship between flowering time and defence response in Arabidopsis (Lyons et al ., ). A negative correlation between flowering and ascochyta blight resistance and co‐localization of QTLs for flowering and ascochyta blight have been reported earlier in chickpea (Daba et al ., ).…”

Arbuscular mycorrhizal fungi promote coexistence and niche divergence of sympatric palm species on a remote oceanic island

“…Second, adaptation to differing microbiomes could have led to a heritable, pleiotropic shift in flowering time. Although many studies have reported a microbial impact on flowering time, including several which have implicated AMF (Gaur et al ., ; Korves & Bergelson, ; Salvioli et al ., ; Wagner et al ., ; Jin et al ., ; Lyons et al ., ; Panke‐Buisse et al ., ), they did not document a genetic explanation for their observations. Because several genes are known to be involved in both pathogen defence and flowering time (Kidd et al ., ; Lai et al ., ; Kazan & Lyons, ), we speculate that adaptation of these genes in response to soil microbes could plausibly cause a shift in flowering time, including in Howea .…”

Pleiotropy in developmental regulation by flowering‐pathway genes: is it an evolutionary constraint?

“…Genes in the autonomous pathway have also been implicated in traits associated with drought response or the balance of water use and photosynthetic efficiency, such as chlorophyll (Chl) accumulation, leaf shape, and inflorescence shape (Mart ınez-Zapater et al, 1995;Henderson et al, 2005). In addition, they are involved in defense against fungal pathogens, response to cold stress, circadian clock regulation, and general vigor (Koornneef et al, 1998;Meier et al, 2001;Kim et al, 2004;Salathia et al, 2006;Veley & Michaels, 2008;Lyons et al, 2015). Because the function of these proteins in RNA processing is highly general, however, it is not always clear whether these effects are mediated by the influence of the autonomous pathway genes on FLC gene expression levels.…”