Effects of Cassava Mosaic Disease on Certain Leaf Parameters of Field-Grown Cassava Clones

Ayanru, D. K. G.

doi:10.1094/phyto-72-1057

Cited by 8 publications

(3 citation statements)

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“…The reduction in the total leaf chl and P n with stress also agrees with previous study and we believe that the reduction of the total leaf chl in virus-infected leaves could be due to degradation of chloroplasts in CMD-infected leaves (Esau 1956), and consequently, less efficient photosynthetic activity is noticed during this period (Tu, Ford, and Krass 1968;Ayanru and sharma 1982;Palta 1990;Carter et al 1992;Fang, Bouwkamp, and Solomos 1998;Raji et al 2013).…”

Section: Discussionsupporting

confidence: 89%

Detection of mosaic virus disease in cassava plants by sunlight-induced fluorescence imaging: a pilot study for proximal sensing

Raji

Subhash

Ravi

et al. 2015

International Journal of Remote Sensing

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Cassava mosaic disease (CMD) is a prominent virus infection that causes considerable crop damage and yield reduction. Early detection of crop damage by remote sensing could be a useful tool for initiating remedial measures to reduce further crop damage. This article presents a non-destructive method for detection and classification of CMD infection, based on the red:far-red chlorophyll (chl) fluorescence image ratio. This pilot study was carried out in 14 varieties of potted cassava plants (Manihot esculenta Crantz) with a multispectral imaging system (MSIS) consisting of an electron multiplying charge coupled device (EMCCD) camera. Sunlight-induced chl fluorescence (SICF) images of plant leaves were recorded using the MSIS at the Fraunhofer lines of O 2 -B at 687 nm and O 2 -A at 759.5 nm and their off-lines at 684 and 757.5 nm. The recorded images were analysed using the Fraunhofer line discrimination (FLD) technique to extract the SICF from the solar reflectance in the recorded images. The chl fluorescence image ratio (red:far-red, F 687 :F 760 ) was computed and correlated with the laser-induced chl fluorescence (LICF) ratio (F 685 :F 735 ) determined by point monitoring, chl content variation, and the net photosynthetic rate (P n ). The scatter plot of the F 687 :F 760 image ratio showed good discrimination between different levels of CMD infection as evidenced by the high sensitivity and specificity values. It is observed that the fluorescence image ratio (F 687 : F 760 ) has a good correlation with P n (coefficient of determination (R 2 ) = 0.85), chl content (R 2 = 0.82), and the LICF ratio (F 685 :F 735 ) (R 2 = 0.80), thereby highlighting the potential of the SICF image ratio in the discrimination of CMD infection. The results clearly indicate that changes in the red:far-red fluorescence image ratio due to CMD stress can easily be detected at an early stage and the technique has great potential for monitoring the health of crops and vegetation from proximal sensing platforms.

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Section: Discussionsupporting

confidence: 89%

Detection of mosaic virus disease in cassava plants by sunlight-induced fluorescence imaging: a pilot study for proximal sensing

Raji

Subhash

Ravi

et al. 2015

International Journal of Remote Sensing

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“…In most of the varieties, diseased plants had lower whitefly infestation than healthy plants. Fewer whiteflies on diseased plants should have been as a result of their emigration to the healthy leaves as less surface area is available for colonization, which occurs as a result of infection by virulent CMB strains (Ayanru and Sharma, 1982;Maruthi 2001;Omongo 2003). This migration thus leads to high spread of CMD in the susceptible cassava varieties.…”

Section: Discussionmentioning

confidence: 99%

Response of Local Cassava Varieties in Uganda to Cassava Mosaic Virus Disease

Adriko¹

2012

AJEA

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Cassava mosaic disease (CMD) resistant varieties have been used to manage CMD in Uganda. In spite the availability of a number of CMD resistant cultivars, several local landraces are continually grown in Uganda because they possess certain desirable traits, which may not have been fully met by the resistant varieties. Field based trials were setup to evaluate the response to CMD of some landraces that became prominent after the 1990s CMD pandemic. Experiments were located in areas where CMD is reported to have subsided namely, Mukono (Central Uganda) and Bulindi (Western Uganda). Three landraces were evaluated per site along with resistant (Nase 4) and susceptible (Bao) standards. Plots were planted with materials obtained from either diseased or healthy fields. The results showed differences in sensitivity to CMD among varieties tested, with landraces consistently having higher CMD incidences than Nase 4. The landraces tested in Mukono were more susceptible to CMD than even the Bao, while at Bulindi on the other hand, only Sibampale proved to be more resistant than Bao. There were differences in the whitefly populations among the cassava varieties and locations. High whitefly populations characterized all landraces and Nase 4. In most tested varieties, there was a higher infestation of whiteflies on healthy than diseased plants. Low spread of CMD among local landraces was observed in Bulindi as would be expected in areas where CMD has almost subsided (low pressure areas). However, in Mukono, disease spread among landraces was very rapid and high CMD incidences reaching 100% were recorded regardless of whether plots were planted with healthy or diseased cuttings suggesting it to be a CMD hot-spot. Thus, the use of clean planting materials as an effective phytosanitary method can only be employed under low disease pressure while high disease pressure areas need use of resistant varieties.

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“…However, the pathogenesis of ACMV is poorly understood. Diminished chlorophyll content (Ayanru and Sharma ) and distorted chloroplasts (Chant and Beck ; Chant et al ) appear on CMV‐infected cassava leaves. Infection with other geminiviruses also causes reduced chlorophyll content, for example, tomato plants infected with Tomato yellow mosaic virus (Leal and Lastra ) and Tomato leaf curl virus (TLCV) infection of the wild plant Eupatorium makinoi (Funayama et al ).…”

Section: Introductionmentioning

confidence: 99%

Why mosaic? Gene expression profiling of African cassava mosaic virus‐infected cassava reveals the effect of chlorophyll degradation on symptom development

Liu

Yang

et al. 2014

JIPB

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Cassava mosaic disease, caused by cassava begomoviruses, is the most serious disease for cassava in Africa. However, the pathogenesis of this disease is poorly understood. We employed high throughput digital gene expression profiling based on the Illumina Solexa sequencing technology to investigate the global transcriptional response of cassava to African cassava mosaic virus infection. We found that 3,210 genes were differentially expressed in virus-infected cassava leaves. Gene ontology term and Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that genes implicated in photosynthesis were most affected, consistent with the chlorotic symptoms observed in infected leaves. The upregulation of chlorophyll degradation genes, including the genes encoding chlorophyllase, pheophytinase, and pheophorbide a oxygenase, and downregulation of genes encoding the major apoproteins in light-harvesting complex II were confirmed by qRT-PCR. These findings, together with the reduction of chlorophyll b content and fewer grana stacks in the infected leaf cells, reveal that the degradation of chlorophyll plays an important role in African cassava mosaic virus symptom development. This study will provide a road map for future investigations into viral pathogenesis.

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Effects of Cassava Mosaic Disease on Certain Leaf Parameters of Field-Grown Cassava Clones

Cited by 8 publications

References 0 publications

Detection of mosaic virus disease in cassava plants by sunlight-induced fluorescence imaging: a pilot study for proximal sensing

Detection of mosaic virus disease in cassava plants by sunlight-induced fluorescence imaging: a pilot study for proximal sensing

Response of Local Cassava Varieties in Uganda to Cassava Mosaic Virus Disease

Why mosaic? Gene expression profiling of African cassava mosaic virus‐infected cassava reveals the effect of chlorophyll degradation on symptom development

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