Effect ofTomato yellow leaf curl bigeminivirus(TYLCV) infection on tomato cell ultrastructure and physiology

Abstract

Tomato yellow leaf curl bigeminivirus was isolated in Kuwait and therefore designated as TYLCV-K. The virus was found to be transmitted by whiteflies (Bemisia tabaci Genn.), and produced the characteristic external symptoms on tomato (Solanum lycopersicum L.) test plants. Electron microscopy of ultra-thin sections of infected leaves showed alterations in the ultrastructure of some organelles and uneven thickenings of the cell wall of the phloem tissue associated with severe damage in chloroplasts and abnormal building up of oily inclusions and empty vacuoles. The causal virus was characterized as a whitefly-transmitted monopartite Geminivirus. Viral genomic DNA fragment of 1.1 kb was successfully amplified from TYLCV-K infected tissues using polymerase chain reaction (PCR). The virus identity was confirmed by using Southern and dot-blot hybridizations. Chemical components of tomato leaves, such as photosynthetic pigments, especially chlorophyll a and b, total lipids, saturated and unsaturated fatty acids, reducing sugars and proteins, decreased in infected leaves when compared with healthy leaves of tomato test plants. On the other hand, total phenols accumulated to a greater extent in infected leaves. However, concentration of ascorbic acid (an antioxidant), leaf extract pH and total fatty acids were not dramatically affected by TYLCV-K. The level of increase or decrease of these constituents varied with different stages of plant growth (depending upon the developmental stages of the leaf at the time of infection). Our study showed that the level of some of the chemical constituents in tomato leaves changed in response to TYLCV-K infection.

In vivo and In vitro evaluation of the antifungal activity of the PGPR Bacillus amyloliquefaciens RaSh1 (MZ945930) against Alternaria alternata with growth promotion influences on Capsicum annuum L. plants

“…11D, F). Similarly, disorganization of the membrane system of the chloroplasts in the infected mesophyll cells, breakdown of the envelope, damage of the cell wall, disappearance of starch grains or the appearance of large starch grains with an increase of plastoglobuli are indicative of infection [121][122][123]. Our results were also in agreement with Gabara et al [124] and Kozieł et al [125].…”

Physiological and transcriptomic analyses revealed gene networks involved in heightened resistance against tomato yellow leaf curl virus infection in salicylic acid and jasmonic acid treated tomato plants

“…Gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases are routinely used to annotate functions of differentially expressed genes (DEGs) in tomato plants. We focused on analysis of genes involved in cell wall biosynthesis as previous reports had shown that tomato leaves infected with TYLCV induced thickening of cell walls ( Montasser et al, 2012 ). We also sought to identify differentially expressed genes in hormone signaling pathways and secondary metabolite regulation.…”

Comparative Study of Bion and Salicylic Acid Applied Through Foliar and Seedling Root Dipping in Tomato Against Alternaria Solani

“…The maximum TSC and TSP were recorded with Bion with foliar application followed by SA and infected control. Montasser et al (2012) Carbohydrates in leaves were significantly decreased in TYLCV isolates infected of tested plant cultivars as compared to healthy ones; this may be due to the defense effect of the plant against the virus infection where the strategy altered from defensive to survival as described by Khalil et al (2014). These results are in harmony with the findings of Radwan et al (2007), Gupta et al (2010).…”