Physiological and Molecular Plant Pathology
Plant defense activators potentiate the generation of elicitor-responsive photon emission in rice
Introduction
The induced resistance response of plants to pathogenic organisms has been of interest in the study of crop protection. Especially in last few decades, the induction of disease resistance in plants as a practical method of crop protection has involved the investigation of several chemicals that induce systemic disease resistance in plants, the so-called ‘plant defense activators’ [1], [2], [3]. Rapid and enhanced defense responses to pathogens/elicitors are characteristic cellular events in plants protected by plant defense activators. This phenomenon has been called ‘priming’ [4]. The priming effects of several defense responses have been reported, including phytoalexin accumulation [5], [6], defense-related gene/protein accumulation [5], [6], [7], [8], [9], and oxidative burst [10], [11]. Priming effects should be useful markers of resistance induction in plant cells [4].
We have already reported a new type of defense-related phenomenon in which plants generate relatively high levels of ultraweak photon emission in an unusual spectrum in response to pathogen attack or elicitor treatment [12], [13], [14]. Living organisms constitutively generate ultraweak photon emissions [15], [16], [17]. The major sources of these in living organisms are thought to be the generation of excited and chemiluminescent molecules and/or energy transfer from excited molecules to fluorescent molecules [15], [18], [19], [20], [21]. This pathogen/elicitor-responsive photon emission could be used as a noninvasive indicator of physiological changes, together with the generation of excited molecules involved in the defense response.
We report here that the generation of elicitor-responsive photon emissions in leaf segments and suspension-cultured cells of rice was potentiated by pretreatment with plant defense activators.
Section snippets
Apparatus for ultraweak photon emission measurement
A multisample photon counter (PCX-100; Hamamatsu K.K., Japan) was used to measure the time-dependent variation in ultraweak photon emission. This device is equipped with an R329P photomultiplier tube, which measures spectral responses ranging from 240 to 630 nm, and a special dark box system for 16 samples. Samples were placed in petri dishes of 60 mm diameter for measurements. Spectrometry of ultraweak photon emission was performed using an MSPC II multisample photon counter (Hamamatsu K.K.,
Elicitor-responsive photon emission from rice leaf segments
Rice leaf segments on distilled water generated ultraweak photon emissions as low as 10 counts s−1 cm−2, with no noticeable changes during the measurements. The PGPF elicitor and PDB themselves emitted photons as low as those emitted by leaf segments (Fig. 1A). Leaf segments floated on PGPF elicitor, however, transiently emitted high levels of photons at over 500 counts s−1 cm−2, with a peak at 6–8 h after application (Fig. 1B). These results indicate that rice leaf segments generate photon emissions
Acknowledgements
This study was supported by a research grant from Shizuoka Prefecture. The authors thank Prof. Mitsuo Hyakumachi for providing the PGPF isolate GP17-2. We are also grateful to Dr Eiichi Minani of the National Institute of Agricultural Resources and Dr Hanae Kaku of Meiji University for their helpful suggestions on the PBZ1 gene expression assay. We are also grateful to Prof. Naoto Shibuya of Meiji University for helpful suggestions about priming effects. We also greatly appreciate the
References (38)
- et al.
Priming in plant–pathogen interactions
Trends Plant Sci
(2002) - et al.
Methyl jasmonate conditions parsley suspension cells for increased elicitation of phenylpropanoid defense responses
Biochem Biophys Res Commun
(1992) - et al.
Aldehyde-enhanced photon emission from crude extracts of soybean seedlings
Biochim Biophys Acta
(1991) - et al.
Oligosaccharide signaling for defence responses in plants
Physiol Mol Plant Pathol
(2001) - et al.
Induction of systemic acquired resistance in plants by chemicals
Annu Rev Phytopathol
(1994) - et al.
Commercial development of elicitors of induced resistance to pathogens
Probenazole—a plant defense activator
Pesticide Outlook
(2001)- et al.
Dichloroisonicotinic and salicylic acid, inducers of systemic acquired resistance, enhance fungal elicitor responses in parsley cells
Plant J
(1992) - et al.
A benzothiadiazole primes parsley cells for augmented elicitation of defense responses
Plant Physiol
(1998) - et al.
Chitinase in cucumber hypocotyls is induced by germinating fungal spores and by fungal elicitor in synergism with inducers of acquired resistance
Plant J
(1998)
Benzothiadiazole-induced priming for potentiated responses to pathogen infection, wounding, and infiltration of water into leaves requires the NPR1/NIM1 gene in Arabidopsis
Plant Physiol
Pretreatment of parsley suspension cultures with salicylic acid enhances spontaneous and elicited production of H2O2
Plant Physiol
Competence for elicitation of H2O2 in hypocotyls of cucumber is induced by breaching the cuticle and is enhanced by salicylic acid
Plant Physiol
Ultraweak luminescence generated by sweet potato and Fusarium oxysporum interactions associated with a defense response
Photochem Photobiol
Spectral shift of ultraweak photon emission from sweet potato during a defense response
Photochem Photobiol
Weak photon emission from the Japanese black pine inoculated with pine wood nematode
Jpn J Phytopathol
Plant chemiluminescence
Annu Rev Plant Physiol
Recent advances in biophoton research and its applications
Biophotonics and coherent systems
Cited by (11)
Application of ultra-weak photon emission measurements in agriculture
2014, Journal of Photochemistry and Photobiology B: BiologyCitation Excerpt :Priming phenomena should be useful markers of defense activation in plant cells [27,46]. Based on the studies of ERPE, we proposed a pilot system for the screening of plant defense activators (Fig. 4) [34]. It takes less than half a day to judge the plant activator ability of a tested compound.
Ultra-weak photon emission from biological samples: Definition, mechanisms, properties, detection and applications
2014, Journal of Photochemistry and Photobiology B: BiologyCitation Excerpt :Similar behavior was observed also in other weeds and plants; Monochoria vaginalis (heartleaf false pickerelweed) [57] rice and 11 species of paddy weeds [58]. Ultra-weak photon emission was also exploited as method for testing new types of agrochemicals that potentiate plants’ defense [56,59]. Additionally, ultra-weak photon emission intensity from germinating seeds was shown to reflect the quality of water used for irrigation [4].
Ultraweak photon emission and proteomics analyses in soybean under abiotic stress
2014, Biochimica et Biophysica Acta - Proteins and ProteomicsCitation Excerpt :Biophoton emissions are stimulated by pathogenic infections in plants. Biophotons are categorized into two types based on the disease-resistance reactions of plants: comparatively weak emissions detected during the initial stages of the resistance response [50], and strong emissions from cells during the middle stages of the resistance response to protect the pathogen from infecting healthy cells where PCD occurred [3]. For instance, PCD exhibited by the inoculation with Fusarium oxysporum in sweet potatoes, and the wavelength composition of photon emission transferred towards relatively shorter wavelengths compared to untreated plants [51].
Sulfonylurea-resistant biotypes of Monochoria vaginalis generate higher ultraweak photon emissions than the susceptible ones
2009, Pesticide Biochemistry and PhysiologySpontaneous ultraweak photon emission from rice (Oryza sativa L.) and paddy weeds treated with a sulfonylurea herbicide
2007, Pesticide Biochemistry and PhysiologyPhoton emissions from rice cells elicited by N-acetylchitooligosaccharide are generated through phospholipid signaling in close association with the production of reactive oxygen species
2006, Plant Physiology and BiochemistryCitation Excerpt :Because photon emissions can be measured in living cells nondestructively, biophotons would be a useful tool for analyzing physiological changes in biological systems. We reported that biophotons were induced by culture filtrations of incompatible organisms such as plant growth-promoting fungi from rice leaf segments or in suspension-cultured rice cells [11]. Bennett et al. [2] showed that biophoton emissions required an intact plant disease-signaling network, and were associated with hypersensitive cell death in Arabidopsis thaliana.