scholarly journals Effects of Bacterial Leaf Blight on Photosynthesis and Chlorophyll a Fluorescence in Susceptible and Resistant Rice Cultivars

2021 ◽  
Vol 25 (02) ◽  
pp. 338-344
Author(s):  
Zengbing Liu
Keyword(s):  
Photosynthetic Reaction Center ◽  
Net Photosynthesis ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Rice Cultivars ◽  
Chl A ◽  
Fluorescence Transient ◽  
Chl A Fluorescence ◽  
Significant Difference ◽  
Negative Effect

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae is a serious disease affecting rice. Understanding of the effects of this disease on photosynthesis and chlorophyll (Chl) a fluorescence is important in rice management. We studied the effect of BLB on enzyme activities, photosynthetic rate (Pn) and Chl a fluorescence transient in susceptible Neiwuyou 8015 and resistant Shenzhou 98 rice cultivars. BLB had a negative effect on rice net photosynthesis (Pn) and stomatal conductance (Gs). Superoxide dismutase (SOD), polyphenol oxidase (PPO), phenylalanine ammonia lyase (PAL) activities, malondialdehyde (MDA) contents were increased while Chl content was decreased, indicating that rice photosynthetic functions were damaged by BLB. The effect of BLB on photosynthesis was greater in susceptible rice than in resistant rice. A significant difference of Chl a fluorescence transient curves was observed between BLB treatments and healthy ones. Parameters measured in transient rice Chl a fluorescence showed the photosynthetic reaction center was inactive after BLB. These findings will help in evaluating rice resistance and may be useful for rice disease management. © 2021 Friends Science Publishers

Non-photochemical quenching of chlorophyll a fluorescence: early history and characterization of two xanthophyll-cycle mutants of Chlamydomonas reinhardtii

2002 ◽  
Vol 29 (10) ◽  
pp. 1141 ◽  
Author(s):  
Govindjee ◽  
Manfredo J. Seufferheld
Keyword(s):  
Chlamydomonas Reinhardtii ◽  
Oxygen Evolution ◽  
Xanthophyll Cycle ◽  
Photochemical Quenching ◽  
Chl A ◽  
Fluorescence Transient ◽  
Chl A Fluorescence ◽  
Non Photochemical Quenching

This paper deals first with the early, although incomplete, history of photoinhibition, of 'non-QA-related chlorophyll (Chl) a fluorescence changes', and the xanthophyll cycle that preceded the discovery of the correlation between non-photochemical quenching of Chl a fluorescence (NPQ) and conversion of violaxanthin to zeaxanthin. It includes the crucial observation that the fluorescence intensity quenching, when plants are exposed to excess light, is indeed due to a change in the quantum yield of fluorescence. The history ends with a novel turn in the direction of research — isolation and characterization of NPQ xanthophyll-cycle mutants of Chlamydomonas reinhardtii Dangeard and Arabidopsis thaliana (L.) Heynh., blocked in conversion of violaxanthin to zeaxanthin, and zeaxanthin to violaxanthin, respectively. In the second part of the paper, we extend the characterization of two of these mutants (npq1, which accumulates violaxanthin, and npq2, which accumulates zeaxanthin) through parallel measurements on growth, and several assays of PSII function: oxygen evolution, Chl a fluorescence transient (the Kautsky effect), the two-electron gate function of PSII, the back reactions around PSII, and measurements of NPQ by pulse-amplitude modulation (PAM 2000) fluorimeter. We show that, in the npq2 mutant, Chl a fluorescence is quenched both in the absence and presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). However, no differences are observed in functioning of the electron-acceptor side of PSII — both the two-electron gate and the back reactions are unchanged. In addition, the role of protons in fluorescence quenching during the 'P-to-S' fluorescence transient was confirmed by the effect of nigericin in decreasing this quenching effect. Also, the absence of zeaxanthin in the npq1 mutant leads to reduced oxygen evolution at high light intensity, suggesting another protective role of this carotenoid. The available data not only support the current model of NPQ that includes roles for both pH and the xanthophylls, but also are consistent with additional protective roles of zeaxanthin. However, this paper emphasizes that we still lack sufficient understanding of the different parts of NPQ, and that the precise mechanisms of photoprotection in the alga Chlamydomonas may not be the same as those in higher plants.

scholarly journals Efektivitas Formulasi Spora Bacillus subtilis B12 sebagai Agen Pengendali Hayati Penyakit Hawar Daun Bakteri pada Tanaman Padi

2015 ◽  
Vol 34 (1) ◽  
pp. 21 ◽  
Author(s):  
Wartono Wartono ◽  
Giyanto Giyanto ◽  
Kikin H. Mutaqin
Keyword(s):  
Bacillus Subtilis ◽  
Plant Growth ◽  
Foliar Spray ◽  
Leaf Blight ◽  
Plant Diseases ◽  
Bacterial Leaf Blight ◽  
Growth Promoter ◽  
Negative Effect ◽  
Plant Growth Promoting ◽  
Blight Disease

<p>Bacterial leaf blight control in rice (Oryza sativa Lin.) using bactericide is prohibitive, due to its high cost and its negative effect on the environment. Biocontrol when avaible, therefore is the best alternative solution. Bacillus subtilis is a perspective of biocontrol agent to control several plant diseases, because of its ability to produce antimicrobial and produce plant growth promoting substances. This research was aimed to examine the effectiveness of B. subtilis spore formulation by way of seed treatments and foliar sprays, using different frequencies and concentrations, to control bacterial leaf blight disease (BLB) on rice, caused by Xanthomonas oryzae pv. oryzae, and to evaluate its function as plant growth promoter. The experiments were conducted at greenhouse and in the field using factorial design. At the greenhouse experiment, seed treatment and foliar spray, using concentration of 2% produced better result in controlling BLB, and better result on promoting rice plant growth. In the field experiment, application at 2 week interval showed better effect on suppressing the the disease and on increasing yield. Applications of the formulation of B. subtilis B12 spore reduced BLB disease by 21% and potentially increased yield up to 50%.</p>

Screening of resistant Indonesian black rice cultivars against bacterial leaf blight

Euphytica ◽  
2018 ◽  
Vol 214 (11) ◽  
Author(s):  
Sutrisno ◽  
Febri Adi Susanto ◽  
Putri Wijayanti ◽  
Mita Dewi Retnoningrum ◽  
Tri Rini Nuringtyas ◽  
...  
Keyword(s):  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Rice Cultivars ◽  
Black Rice

scholarly journals The Role of Nanochitosan on the Expression of Rice Resistance Genes against Bacterial Leaf Blight

2020 ◽  
Vol 24 (2) ◽  
pp. 115
Author(s):  
Siswanti Siswanti ◽  
Tri Joko ◽  
Siti Subandiyah
Keyword(s):  
Resistance Genes ◽  
Rapid Evolution ◽  
Rice Cultivar ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Distilled Water ◽  
Disease Symptoms ◽  
Resistant Varieties ◽  
Significant Difference

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) has been reported to cause ± 20–50% of rice yield loss around the world. Resistant varieties are used to control this disease, however due to rapid evolution of this pathogen, the resistances was broken down in a few years. This study is aimed to determine the role of nanochitosan in the expression of rice Xa21 and Xa1 resistant genes against Xoo. The BLB susceptible rice cultivar IR64, the Xoo isolate MAG2 and a 0.065% concentration of nanochitosan were used in this experiment. Application of nanochitosan was carried out within 1-week intervals starting at rice aged 2–10 weeks after transplanting. The expression of Xa21 and Xa1 genes against Xoo were analyzed using conventional PCR and qPCR methods at 0 and 4 days after Xoo inoculation followed by 4x scoring of disease symptoms in 1-week interval. The treatments used in this study included the mock one/inoculated with sterile distilled water, K (+)/ plants inoculated with Xoo, CNP (-)/ with nanochitosan and sterile distilled water inoculation, and CNP (+)/ with nanochitosan and Xoo inoculation. The results showed that the 0.0065% concentration nanochitosan application was able to increase the expression of Xa21 and Xa1 genes on CNP (-). Disease intensity and AUDPC values did not show any significant difference between K (+) and CNP (+). This study concluded that nanochitosan at 0.065% was able to increase the expression of rice Xa21 and Xa1 resistance genes. However, the gene expression was not able to significantly suppress the infection development of Xoo.

Thylakoid membrane model of the Chl a fluorescence transient and P700 induction kinetics in plant leaves

2016 ◽  
Vol 130 (1-3) ◽  
pp. 491-515 ◽  
Author(s):  
N. E. Belyaeva ◽  
A. A. Bulychev ◽  
G. Yu Riznichenko ◽  
A. B. Rubin
Keyword(s):  
Thylakoid Membrane ◽  
Membrane Model ◽  
Plant Leaves ◽  
Chl A ◽  
Fluorescence Transient ◽  
Induction Kinetics ◽  
Chl A Fluorescence

scholarly journals DETECTION OF GENES RESISTANT TO BACTERIAL LEAF BLIGHT IN RICE CULTIVARS FROM SITUBONDO AND JEMBER, INDONESIA

2019 ◽  
Vol 19 (2) ◽  
pp. 127
Author(s):  
Rasmiyana ., ◽  
Hardian Susilo Addy ◽  
Erlia Narulita
Keyword(s):  
Resistance Genes ◽  
Sampling Method ◽  
Disease Incidence ◽  
Leaf Blight ◽  
Bacterial Leaf Blight ◽  
Rice Cultivars ◽  
Average Temperature ◽  
Resistant Varieties ◽  
The Impact ◽  
Generative Stage

Detection of genes resistant to bacterial leaf blight in rice cultivars from Situbondo and Jember, Indonesia. Xanthomonas oryzae pv. oryzae (Xoo), causing bacterial leaf blight, is a destructive pathogen that significantly affects rice production. The use of resistant varieties is the most effective and economical strategy to reduce the impact of the disease. This study aimed to analyze the genetic basis of resistance to Xoo in rice. The incidence and severity of bacterial leaf blight were assessed in the field through a diagonal random sampling method. PCR was used to detect resistant genes in rice with eight Xa-specific primers. The presence of Xa genes and environmental conditions were statistically analyzed to determine whether the disease incidence and disease severity were related to average temperature and rain intensity. The means for disease incidence and severity at the generative stage were higher than those at the vegetative stage. The 12 rice cultivars were categorized into four groups based on the presence of Xa gene sequences; most cultivars had Xa10 and Xa13, and one cultivar had five Xa genes. Disease incidence and severity were weakly correlated to the presence of resistance genes, as well as to environmental factors. Most rice cultivars from the Regencies of Jember and Situbondo carry Xa10 and Xa13 resistance genes.

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