Influence of Environmental Conditions and Genetic Background of Arabica Coffee (C. arabica L) on Leaf Rust (Hemileia vastatrix) Pathogenesis

Abstract

Global warming is a major threat to agriculture worldwide. Between 2008 and 2013, some coffee producing countries in South and Central America suffered from severe epidemics of coffee leaf rust (CLR), resulting in high economic losses with social implications for coffee growers. The climatic events not only favored the development of the pathogen but also affected the physiological status of the coffee plant. The main objectives of the study were to evaluate how the physiological status of the coffee plant modified by different environmental conditions impact on the pathogenesis of CLR and to identify indicators of the physiological status able to predict rust incidence. Three rust susceptible genotypes (one inbred line and two hybrids) were grown in controlled conditions with a combination of thermal regime (TR), nitrogen and light intensity close to the field situation before being inoculated with the rust fungus Hemileia vastatrix. It has been demonstrated that a TR of 27-22°C resulted in 2000 times higher sporulation than with a TR of 23–18°C. It has been also shown that high light intensity combined with low nitrogen fertilization modified the CLR pathogenesis resulting in huge sporulation. CLR sporulation was significantly lower in the F1 hybrids than in the inbred line. The hybrid vigor may have reduced disease incidence. Among the many parameters studied, parameters related to photosystem II and photosynthetic electron transport chain components appeared as indicators of the physiological status of the coffee plant able to predict rust sporulation intensity. Taken together, these results show that CLR sporulation not only depends on the TR but also on the physiological status of the coffee plant, which itself depends on agronomic conditions. Our work suggests that vigorous varieties combined with a shaded system and appropriate nitrogen fertilization should be part of an agro-ecological approach to disease control.

G × E interactions on yield and quality in Coffea arabica: new F1 hybrids outperform American cultivars

“…Among these performing hybrids genotypes (for yield and stability), Centroamericano-H1 and Mundo Maya-H16 are resistant to rust disease while Evaluna-H18 and Nayarita-H19 are weakly susceptible to rust. Many studies have shown that plant rust incidence is linked to productivity (Avelino et al 2006;Toniutti et al 2017Toniutti et al , 2019. In our study, the GSI index (which takes into account both productivity and productivity stability) is not related to the level of rust incidence.…”

“…In theory, this higher genetic potential also means it is more likely to be adaptable across a wide range of environments. In previous works we showed that Arabica F1 hybrids produced more than their parents (Bertrand et al 2005) and also eliminate many of the trade-offs of the past-for example, coffee leaf rust resistance versus quality (Toniutti et al 2017).…”

Views from two mountains: exploring climate change impacts on traditional farming communities of Eastern Africa highlands through participatory scenarios

“…Globally suitable agro-climatic zones for growing Coffee arabica are expected to significantly diminish, although increased temperature could favour its production at higher elevation and close to the Equator (Ovalle-Rivera et al 2015). With higher temperatures increased potential damage by coffee berry borer Hypothenemus hampei (Jaramillo et al 2011) and coffee leaf rust Hemileia vastatrix disease (Toniutti et al 2017) are expected.…”

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“…Manual thinning by coffee workers to reduce fruits by 50% (which in fact reduced yield 38%) resulted in between 4 to 6% of lower RI (respectively for the inbred and the hybrid). Similar results by (Toniutti 2017) confirmed that CLR sporulation depends on the physiological status of the coffee plant, which itself depends on agronomic conditions and on hybrid vigour. Here we focused on the transcriptome of the coffee leaf response from these agronomic management strategies to control coffee leaf rust disease (CLR).…”