Nowadays, Huanglongbing (HLB) disease, associated with Candidatus Liberibacter asiaticus (CLas), seriously affects citriculture worldwide, and no cure is currently available. Transcriptomic analysis of host–pathogen interaction is the first step to understand the molecular landscape of a disease. Previous works have reported the transcriptome profiling in response to HLB in different susceptible citrus species; however, similar studies in tolerant citrus species, including Mexican lime, are limited. In this work, we have obtained an RNA-seq-based differential expression profile of Mexican lime plants challenged against CLas infection, at both asymptomatic and symptomatic stages. Typical HLB-responsive differentially expressed genes (DEGs) are involved in photosynthesis, secondary metabolism, and phytohormone homeostasis. Enrichment of DEGs associated with biotic response showed that genes related to cell wall, secondary metabolism, transcription factors, signaling, and redox reactions could play a role in the tolerance of Mexican lime against CLas infection. Interestingly, despite some concordance observed between transcriptional responses of different tolerant citrus species, a subset of DEGs appeared to be species-specific. Our data highlights the importance of studying the host response during HLB disease using as model tolerant citrus species, in order to design new and opportune diagnostic and management methods.

The Annonaceae family is one of the oldest angiosperms. The genus Annona is the one with the most species and, together with Asimina, the only ones that contain edible fruits. In the last 10 years, interest in these fruit species has increased, mainly due to their nutritional properties and their application in the treatment of human diseases. Mexico is the center of origin for most of them. However, at present much of the basic agronomic information, postharvest handling of the fruits, and their potential as new crops for areas with poor soils in organic matter or semi-dry climates is unknown. It is considered that these custard apple species may be an option to change towards instead of crops that have lost profitability and sustainability. A review of the current state of knowledge in different areas of the species A. muricata, A. macroprophyllata, A. reticulata, A. squamosa, and A. cherimola was carried out and to focus research efforts on the topics of greatest interest and on those where is required to achieve a sustainable production and use of these resources in Mexico. However, knowledge about the cultivation and potential uses of these species is needed to increase their commercialization; the integration of interdisciplinary and interinstitutional groups is required.

Resumen. El psílido asiático de los cítricos (PAC; Diaphorina citri) es la plaga más importante que afecta a la lima mexicanao (Citrus aurantifolia) en el trópico seco de México y es el vector de la enfermedad del Huanglongbing. Su control se basa en el uso de insecticidas sintéticos. La búsqueda de alternativas sustentables y eficaces es una prioridad en el manejo del PAC. En este estudio, se evaluó el efecto de diferentes tipos de aceites y extractos de plantas en el control de ninfas del PAC en el estado de Colima, México. Las pruebas fueron conducidas en árboles de lima mexicana y plantas de vivero infestadas con la plaga. Se realizó una aplicación foliar de cada tratamiento sobre brotes vegetativos de 5 a 7 días de edad. Las evaluaciones del número de ninfas vivas se hicieron antes y después de la aplicación de los aceites y los extractos de plantas. En la primera prueba, el aceite parafínico (99% de residuos no sulfonados) a concentraciones de 1, 2, y 3%, redujeron la población del PAC entre un 77 a... The Asian citrus psyllid (ACP; Diaphorina citri) is the most important pest affecting Mexican lime (Citrus aurantifolia) in the dry tropics of Mexico, and is the vector of huanglongbing disease. Its control is based on synthetic insecticides. The search for sustainable and effective alternatives is a priority in the management of ACP. In this study, the effect of different kinds of oils and plant extracts were evaluated to control ACP nymphs in Colima, Mexico. The tests were conducted on mature Mexican lime trees and nursery plants infested with the pest. One foliar application of each treatment was done to tagged 5-7 d shoots. Paraffinic oil (99% of unsulfonated residues) at 1, 2, and 3%, reduced the ACP population between 77 to 98% as compared with the untreated control. Different paraffinic oils, cooking oils, and citrus oil maintained a low infestation of ACP compared to the control. Also, neem, garlic, and onion extracts showed a significant reduction of ACP nymphs. Jatropha curcas seed oil...

The citrus disease known as Huanglongbing (HLB) is one of the most important worldwide. Present in Mexico since 2009, its current management is carried out mainly through population monitoring and control of its insect vector, Diaphorina citri with the use of insecticides and natural enemies. The objective of this research was to estimate the spatio-temporal distribution of Diaphorina citri populations in Persian lime Citrus latifolia with a regional management scheme in Nayarit, Mexico. The study was conducted in 2018-2020 in two environments: warm subhumid and semi-warm subhumid. Temporal fluctuation and spatial distribution were obtained by capturing psyllid adults in orchards in both climatic zones with 2.041 yellow traps, which were reviewed biweekly. Analysis of variance of the number of adults was carried out between localities, by climatic zone and between months of the year. Correlations between populations and temperature and rainfall were estimated. The adult population of D. citri was statistically similar between orchards in the same climatic zone, for which the same management by climatic zone is justified. In both climates, a significant difference in populations of D. citri was detected between the months of the year. In warm subhumid climate, the highest adult populations of D. citri were recorded in July and August, so it would be necessary to apply a control measure in this period. In semi-warm subhumid climates, the highest adult populations of the psyllid occurred in February-March and August, in this period is recommended to apply a control measure. In this study, no significant correlation was detected between populations of D. citri with temperature or rainfall. Control of D. citri can be regional, differentiated in each climatic zone and according to the months of the year with the largest population.

Limes and lemons are grown in 107 countries, in an area of 983,657 hectares, from which more than 15 million tons of fruits were obtained in 2012, which represents 13% of the total citrus fruit produced in the world. Three species of citrus are grown internationally, which due to their acidic taste and the use that consumers give them, mainly in the preparation of soft drinks and dressings for meals, are considered lemons. In Mexico, the production of Mexican lime [Citrus aurantifolia (Christm.) Swingle] is of great economic and social importance. It grows on 81,221.9 hectares distributed in 24 federal entities. Of these, Michoacán, Colima, Oaxaca, and Guerrero with 42,931, 18,996, 6843, and 6856 hectares, respectively, are the most important. The annual production of fruit recorded in 2013 exceeded 1.04 million tons, with a value of 3371 million pesos. The Mexican lime production system generates many jobs practically all year round, both for crop management and in the harvest and processing of fruit. In addition, there are a considerable number of plant-producing nurseries and input-providing companies that benefit from the cultivation of this citrus. This chapter describes the studies on the development and innovation of techniques in Mexican lemon carried out during the last 25 years in Mexico, such as induced mutation and manual hybridization for the generation of new varieties, as well as the use of interstocks and the evaluation of new genotypes with desirable characteristics. On the other hand, propagation and establishment in the field are fundamental points for a good development and production of Mexican lime.