Leaf Gas Exchange and Chlorophyll a Fluorescence Imaging of Rice Leaves Infected with Monographella albescens

Abstract

This study was intended to analyze the photosynthetic performance of rice leaf blades infected with Monographella albescens by combining chlorophyll (Chl) a fluorescence images with gas exchange and photosynthetic pigment pools. The net CO2 assimilation rate, stomatal conductance, transpiration rate, total Chl and carotenoid pools, and Chl a/b ratio all decreased but the internal CO2 concentration increased in the inoculated plants compared with their noninoculated counterparts. The first detectable changes in the images of Chl a fluorescence from the leaves of inoculated plants were already evident at 24 h after inoculation (hai) and increased dramatically as the leaf scald lesions expanded. However, these changes were negligible for the photosystem II photochemical efficiency (Fv/Fm) at 24 hai, in contrast to other Chl fluorescence traits such as the photochemical quenching coefficient, yield of photochemistry, and yield for dissipation by downregulation; which, therefore, were much more sensitive than the Fv/Fm ratio in assessing the early stages of fungal infection. It was also demonstrated that M. albescens was able to impair the photosynthetic process in both symptomatic and asymptomatic leaf areas. Overall, it was proven that Chl a fluorescence imaging is an excellent tool to describe the loss of functionality of the photosynthetic apparatus occurring in rice leaves upon infection by M. albescens.

Photosynthetic and antioxidative alterations in coffee leaves caused by epoxiconazole and pyraclostrobin sprays and Hemileia vastatrix infection

“…It is known that photoinactivation can lead to oxidative damage and loss of PSII reaction centers [55], both of which are associated with an increase in F0 [54]. A reduction in Fv/Fm and increase in F0 are consistent with the reports of rice-Monographella albescens, corn-Stenocarpella macrospora, wheat-Pyricularia oryzae and eucalyptus-Puccinia psidii interactions [56][57][58][59]. The negative effect of H. vastatrix on the photosynthesis of coffee leaves were clearly demonstrated by the Chl a fluorescence parameters studied.…”

Biodiversity of fungi on Vitis vinifera L. revealed by traditional and high-resolution culture-independent approaches

“…However, some species of this genus can be pathogenic to some economically important crops (Fitt et al 2006). Monographella is a known leaf pathogen on rice, barley, maize and wheat (Daamen et al 1991;Hock et al 1992;Tatagiba et al 2015). However, there are no records of species of this genus associated with grapevine.…”

Chlorophyll a fluorescence imaging of soya bean leaflets infected by Corynespora cassiicola

“…syringae and rice-Monographella albescens interactions, the F v /F m parameter significantly decreased on diseased leaf tissue compared to nondiseased ones (Bonfig, Schreiber, Gabler, Roitsch, & Berger, 2006;Iqbal, Goodwin, Leonardos, & Grodzinsli, 2012;Tatagiba et al, 2015).…”

“…The changes in the values of the F v / F m , Y(II), ETR, Y(NPQ) and Y(NO) parameters in the inoculated leaflets may be explained, at least in part, by the nonhost selective toxins and hydrolytic enzymes released by C. cassiicola which contribute to cause intense leaf tissue disorganization and further necrosis (Fortunato et al., ). For the Arabidopsis thaliana ‐ Pseudomonas syringae , Nicotiana benthamiana‐P.syringae and rice‐ Monographella albescens interactions, the F v / F m parameter significantly decreased on diseased leaf tissue compared to nondiseased ones (Bonfig, Schreiber, Gabler, Roitsch, & Berger, ; Iqbal, Goodwin, Leonardos, & Grodzinsli, ; Tatagiba et al., ).…”

“…To the best of the authors' knowledge, the present study is the first to report that the photosynthetic performance, denoted by examining Changes in photosynthesis rates in many host-pathogen interactions have been intensively investigated using the Chl a fluorescence imaging technique (Scholes & Rolfe, 2009;Tatagiba, DaMatta, & Rodrigues, 2015). In general, the damage caused by pathogens of different lifestyles (biotrophics, hemibiotrophics and necrotrophics) on the leaf can be detected due to an decrease on A, g s , E and F v /F m values (Debona et al, 2014;Dias et al, 2018;Honorato Júnior et al, 2015;Lopes & Berger, 2001;Rolfe & Scholes, 2010;Tatagiba et al, 2015Tatagiba et al, , 2016. For reflecting the quantum efficiency of the PSII, the F v /F m parameter has been used as an excellent indicator of how the plants can support a certain level of stress (Maxwell & Johnson, 2000).…”