Elucidation of Physio-Biochemical Changes in Citrus spp. Incited by Xanthomonas citri pv. citri

Abstract

India is one of the leading citrus−producing countries, next to China and Brazil. Despite the sizeable production, especially of lemons and limes, India contributes meagerly to the world’s citrus market. Of the various factors responsible for the restricted quantum of citrus export, citrus canker (Xanthomonas citri pv. citri) is one of the leading serious causes and directly impacts the appearance of the fruits. Considering the extent of damage, the present study aimed to understand the impact of Xanthomonas citri pv. citri (Xcc) on the physio−biochemical responses in contrasting Citrus spp. Two genotypes, each of three citrus species, namely Citrus aurantifolia (Pusa Udit and ALC−35), C. limon (Kagzi Kalan and Konkan Seedless), and C. paradisi (Redblush and Marsh Seedless), were artificially inoculated with Xcc (108 to 109 cfu/ mL) by the pinprick method. The physio−biochemical changes in the host were evaluated after 48 h post inoculation (hpi). The chlorophyll content (total, a, and b) degradation and reduction in leaf gas exchange parameters, such as photosynthetic rate (A), transpiration rate (E), stomatal conductance (gs), and intrinsic water−use efficiency (iWUE), were measured to a greater extent in susceptible than resistant genotypes. The microscopic observations also evidenced higher stomatal density with larger stomatal areas in susceptible genotypes, favoring the easier penetration of Xcc in host tissues than resistant species or genotypes. The higher activities of various antioxidant enzymes, viz., superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione reductase (GR), the contents of soluble protein, and phenolics were measured in resistant genotypes in contrast to susceptible genotypes. The activities of phenyl ammonia lyase (PAL) and polyphenol oxidase (PPO) were also higher in resistant genotypes, whilst the levels of ROS (superoxide radical and hydrogen peroxide) production were enhanced in susceptible genotypes. Based on the host–pathogen interaction, the order of resistance in a descending manner was found as Kagzi Kalan, Marsh Seedless, Redblush, Konkan Seedless, Pusa Udit, and ALC−35. Further, the results will enhance the understanding of the pathogen mechanism during pathogenesis in resistant and susceptible Citrus species.

Analysis of growth dynamics in five different media and metabolic phenotypic characteristics of Piriformospora indica

“…Additionally, P. indica could produce spores in most of the growable osmotic pressure and pH conditions. Obviously, P. indica has a wide range of environmental adaptability, which is consistent with its ability to colonize a variety of plant hosts (Qiang et al, 2012 ; Manzar et al, 2022b ; Mahawer et al, 2023 ).…”

Effect of Different Plant Spacing on Growth, Yield and Fruit Quality of Kinnow Mandarin Citrus reticulata in Sargodha, Punjab, Pakistan

“…Across the globe, cultivation of citrus fruits has spread to more than 140 countries on an of about 495199.184 acres with estimated yearly production of 158 million tons (Mahawer et al, 2023). Tropical and subtropical areas around the equator with latitudes of 35 • N and 35 • S in Northern Hemisphere are hub of citrus production (Ramana et al, 1981;UNCTAD, 1991).…”