CITRUS ROOTSTOCK SELECTION FOR ENHANCED HUANGLONGBING RESISTANCE: A STRATEGIC DISEASE MANAGEMENT PARADIGM

Citrus fruits, widely cultivated in tropical and subtropical regions, face considerable challenges, notably from the destructive citrus greening disease (HLB).This is caused by Candidatus Liberibacter spp., bacteria transmitted by psyllids, significantly reducing citrus yield and quality and posing a global threat to citrus production.Eliminating Huanglongbing (HLB) disease remains a challenge due to the lack of an effective cure, necessitating the adoption of a practical short-term management method known as the "Three-pronged" strategy.The practice of traditional plant breeding struggles to overcome two main hurdles including inter-species compatibility problems and extended juvenile phases.The use of disease-resistant rootstocks improves citrus plant tolerance against HLB which provides an effective solution to minimize damage from the disease.We examined three citrus rootstocks together with four graft combinations.The side grafting technique served to introduce the Candidatus Liberibacter asiaticus (CLas) to the citrus plants.Furthermore, the inoculation with CLas resulted in significant reductions of chlorophyll a, chlorophyll b, and total chlorophyll content, while photosynthetic activity and chlorophyll fluorescence intensity declined in various citrus varieties.Additionally, the inoculation led to a marked increase in reactive oxygen species (ROS), hydrogen peroxide (H2O2), and malondialdehyde (MDA) levels, indicating heightened oxidative stress.Interestingly, the varieties 'Jiu Bing Le' and 'Hong Jiang'/'Jiu Bing Le' exhibited minimal damage, suggesting a high degree of resilience and potential resistance to the disease.