Pectinolytic plant-bacteria members of the
Pectobacterium
genera represent an important threat to potato (
Solanum tuberosum
L.) cultivation worldwide. Despite several
Pectobaterium
species having ...been described infecting cultivated plants in Mexico, studies of its occurrence in economically important crops including potato are limited. In the present study, 51
Pectobacterium
isolates were obtained from potato plants collected in January 2020 in Sinaloa state, showing blackleg and soft rot symptoms. Biochemical and molecular analysis confirmed that 13 out of the 51 obtained isolates corresponded to
Pectobacterium punjabense
. Virulence analysis of LFLA-136 and LFLA-138 representative isolates showed that both display similar levels of aggressiveness with different tuber maceration capacities on the two evaluated potato varieties. Additionally, putative control strategies were evaluated by
in vitro
inhibition assays using chemical and biological products, with biological control by
Trichoderma harzianum
(T-22) being the most effective treatment. Our data highlights the importance of studying the occurrence of
Pectobacterium
species infecting potatoes in Mexico. To our knowledge, this is the first report of
P. punjabense
causing soft rot and blackleg of potato in Mexico.
Huanglongbing (HLB), one of the most devastating citrus diseases in the world, was detected in Mexico in 2009. Currently, HLB is associated with the bacteria Candidatus Liberibacter spp., although ...several phytoplasmas have been found from trees showing HLB-like symptoms in Brazil and China. The aim of this study was thus to determine if, in addition to ‘Ca. L. asiaticus’ (CLas), phytoplasma species are also associated with HLB-like symptoms in citrus groves of Mexico. Citrus plants exhibiting symptoms such as diffuse chlorosis, blotchy mottle and vein yellowing were collected in the Mexican States of Nayarit, Colima and Sinaloa between August 2011 and September 2012. Samples were then evaluated for phytoplasmas and CLas by PCR, using primers that respectively target the genes for the 16S ribosomal RNA and 50S ribosomal protein of the β operon (rplA-rplJ). Out of 86 HLB-symptomatic citrus plants, 54 were positive for CLas, 20 were positive for phytoplasmas, 7 were found in mixed infections with both pathogens and 19 samples were negative for CLas and phytoplasmas. Actual and virtual RFLP analyses of the 16S rDNA sequences enabled us to classify two HLB phytoplasma strains as members of the aster yellows group (16SrI) ‘Candidatus Phytoplasma asteris’, which was confirmed by phylogenetic analysis. The HLB phytoplasma strain identified from Nayarit (HLBpc-Nay-IB) belongs to subgroup B (16SrI-B), and the strains identified from Colima (HLBpc-Col-IS) and Sinaloa (HLBpc-Sin-IS) belong to subgroup S (16SrI-S). The partial ‘Ca. L. asiaticus’ rplA-rplJ gene sequences were 100% identical to the ‘Ca. L. asiaticus’ strains isolated from several countries affected by HLB. These results confirm the association of ‘Candidatus Phytoplasma asteris’ with HLB-like symptoms in citrus groves in Mexico. Nonetheless, further studies are required to fully describe the ‘Ca. L. asiaticus’ and ‘Ca. P. asteris’ interactions in citrus, which will greatly assist the design of efficient management strategies.
•Ca. L. asiaticus and two strains of Ca. P. asteris are associated with HLB disease in citrus in Mexico.•Phytoplasmas were detected in 23.3% of citrus plants exhibiting HLB symptoms.•Phytoplasmas were detected in mixed infections with Clas in 8.1% of citrus plants exhibiting HLB symptoms.
The citrus industry is of great importance in Mexico, with an estimated production value of USD 2.4 billion and the potential to generate up to 28 million employees per year. Approximately 69,000 ...Mexican families depend on this sector. However, it is under serious threat from the disease known as Huanglongbing (HLB). The rapid spread of this disease has caused significant economic losses, impacted the livelihoods of citrus growers, and led to substantial job losses. Currently, HLB is not under control in Mexico, and as the management strategies applied have proven to be ineffective, yields have not been recovered to pre-HLB levels, and production costs have significantly increased. Therefore, it remains the most destructive citrus disease. This review paper describes the current situation of the disease, its economic and social impact, and the measures adopted for its management in Mexico. Future perspectives highlight advances in research based on new biotechnological tools as an eco-friendly management alternative. Practical suggestions to address HLB are also mentioned in our analysis.
Huanglongbing (HLB) is one of the most destructive diseases threatening citriculture worldwide. This disease has been associated with α-proteobacteria species, namely
Liberibacter. Due to the ...unculturable nature of the causal agent, it has been difficult to mitigate the disease, and nowadays a cure is not available. MicroRNAs (miRNAs) are key regulators of gene expression, playing an essential role in abiotic and biotic stress in plants including antibacterial responses. However, knowledge derived from non-model systems including
Liberibacter asiaticus (
Las)-citrus pathosystem remains largely unknown. In this study, small RNA profiles from Mexican lime (
) plants infected with
Las at asymptomatic and symptomatic stages were generated by sRNA-Seq, and miRNAs were obtained with ShortStack software. A total of 46 miRNAs, including 29 known miRNAs and 17 novel miRNAs, were identified in Mexican lime. Among them, six miRNAs were deregulated in the asymptomatic stage, highlighting the up regulation of two new miRNAs. Meanwhile, eight miRNAs were differentially expressed in the symptomatic stage of the disease. The target genes of miRNAs were related to protein modification, transcription factors, and enzyme-coding genes. Our results provide new insights into miRNA-mediated regulation in
in response to
Las infection. This information will be useful to understand molecular mechanisms behind the defense and pathogenesis of HLB.
Nowadays, Huanglongbing (HLB) disease, associated with
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 pathogenicity of 10 bacterial isolates was investigated on potato, radish, carrot and beet, including sensitivity and pathogen control efficacy. The isolates were identified by morphological, ...biochemical and molecular methods. All isolates were pathogenic on radish, carrot, and beet, and were highly virulent on potato. Although the isolates were obtained from different locations in the El Fuerte Valley (Sinaloa, Mexico), they were similar in their morphological, physiological and biochemical characteristics. Sequences of the 16S rRNA gene obtained by PCR were identical for all isolates. These results indicate that the bacterial isolates from potato scabby tissue belong to
S. acidiscabies
. Furthermore, the effectiveness of fluazinam, both in vitro and under greenhouse and field conditions, represents a possible
option for chemical control of potato common scab disease. While our results suggest that spraying at seeding is effective in controlling common scab, future studies to combine this treatment with seed dressing before planting will be conducted to determine if there is an increase in disease control.
Potato plants infected by phytoplasmas exhibit an array of symptoms that suggest interference within the normal balance of plant metabolism. Suppression subtractive hybridization (SSH), macroarray ...screening and real-time PCR were performed to identify differentially expressed genes in phytoplasma-infected in vitro potato plants. Gene expression analysis revealed the up-regulation of genes involved in several metabolic pathways, including ERF, WRKY, HSP90, SAP6, AN1-like ZFP, and an unknown protein; the down-regulation of genes encoding monodehydroascorbate reductase and a putative membrane protein was also observed. The results presented here provide the groundwork for addressing new questions to better understand the phytoplasma–plant interaction.
► We identify differentially expressed genes in MPPTP infected in vitro potato plants. ► MPPTP alters expression of genes involved in several metabolic pathways. ► Our results showed up regulation of genes ERF, WRKY, HSP90, SAP6, AN1-like ZFPs.
A new fungal disease of inflorescences of Mexican nut (Jatropha curcas L.) was found on plants in two experimental fields located in Sinaloa, Mexico during summer 2011. The fungus caused ...inflorescence blight on flowers with typical symptoms of dark brown necrotic lesions; both plantations of J. curcas had disease incidence of 50–60%. Based on cultural and morphological characteristics and ribosomal DNA spacer sequences, the pathogen was identified as Alternaria alternata (Fr.) Keissler. To our knowledge, this is the first report of Alternaria inflorescence blight disease in J. curcas in Mexico.
We report for the first time the antioxidant and antimutagenic activities of fractions from Randia echinocarpa fruit, which is a Rubiaceae plant native to Sinaloa, Mexico. This fruit has been ...traditionally used in the prevention or treatment of cancer, among other diseases. The pulp of the fruit was sequentially extracted with solvents of different polarity (i.e. hexane, chloroform, methanol and water). A high extraction yield was obtained with methanol (72.17% d.w.). The aqueous extract showed the highest content of phenolics (2.27 mg/g as ferulic acid equivalents) and the highest antioxidant activity based on the β-carotene bleaching method (486.15). The commercial antioxidant BHT was used as control (835.05). Antimutagenic activity of the aqueous extract (0-500 μg/tube) was evaluated using the Salmonella microsuspension assay (YG1024 strain) and 1-NP as the mutagen (50 and 100 ng/tube). The aqueous extract was neither toxic nor mutagenic and the percentage of inhibition on 1-NP mutagenicity was 32 and 53% at doses of 50 and 100 ng/tube, respectively. The results of the double incubation assay suggest that the extract inhibited the mutagenicity of 1-NP by a combination of desmutagenic and bioantimutagenic effects.
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