Phenotyping Plant Responses to Biotic Stress by Chlorophyll Fluorescence Imaging

Abstract

Photosynthesis is a pivotal process in plant physiology, and its regulation plays an important role in plant defense against biotic stress. Interactions with pathogens and pests often cause alterations in the metabolism of sugars and sink/source relationships. These changes can be part of the plant defense mechanisms to limit nutrient availability to the pathogens. In other cases, these alterations can be the result of pests manipulating the plant metabolism for their own benefit. The effects of biotic stress on plant physiology are typically heterogeneous, both spatially and temporarily. Chlorophyll fluorescence imaging is a powerful tool to mine the activity of photosynthesis at cellular, leaf, and whole-plant scale, allowing the phenotyping of plants. This review will recapitulate the responses of the photosynthetic machinery to biotic stress factors, from pathogens (viruses, bacteria, and fungi) to pests (herbivory) analyzed by chlorophyll fluorescence imaging both at the lab and field scale. Moreover, chlorophyll fluorescence imagers and alternative techniques to indirectly evaluate photosynthetic traits used at field scale are also revised.

Boosting photosynthetic machinery and defense priming with chitosan application on tomato plants infected withFusarium oxysporumf. sp.lycopersici

“…Meanwhile, excess energy is harmlessly dissipated as heat (non-photochemical quenching) or fluorescence, to avoid damage to the leaf. In this way, chlorophyll fluorescence is one of the best indicators for detecting early stress in plants since damage to PSII is avoided, and photosynthetic activity is preserved through energy dissipation as an acclimatization mechanism ( Pérez-Bueno et al, 2019;Azcón-Bieto and Talón, 2008).…”

Complexity of Brassica Oleracea-Alternaria Brassicicola Susceptible Interaction Reveals Down-regulation of Photosynthesis at Ultrastructural, Transcriptional and Physiological Levels

“…The reduction of photosynthesis, determined by a decrease in the effective quantum yield of PSII, has been previously observed in the interaction of B. juncea-A. brassicicola [9] and in other plants infected with necrotrophic fungi [84,85]. Also, in wheat plants infected with Bipolaris sorokiniana, a decrease in F v /F m correlated with the loss of chlorophyll has been noted [86].…”

“…Also, in other plants (i.e. rice, tomato) exposed to necrotrophic fungi, a signi cant decrease in NPQ was observed both in the necrotic zone and in adjacent areas of the leaf blade, without signi cantly reducing the photosynthesis e ciency (measured as F v /F m ) [85,90].…”

Rapid On-Site Phenotyping via Field Fluorimeter Detects Differences in Photosynthetic Performance in a Hybrid—Parent Barley Germplasm Set

“…The use of handheld devices like the one used in our study enables assessing photosynthetic performance at large-scale and affordable price, under field conditions, and opens the possibility to explore traits that were understudied in crop genetics. This type of proximal measurements, as well as the emerging field of solar-induced chlorophyll fluorescence (SiF), which has the additional advantage of being amenable to remote measurement [64,65], and could become useful additions to the breeders' toolbox.…”