Transcriptional regulation of cell growth and reprogramming of systemic response in wheat (Triticum turgidum subsp. durum) seedlings by Bacillus paralicheniformis TRQ65

Bacillus paralicheniformis TRQ65 reprograms the gene expression patterns associated with systemic response to potentially facilitate its colonization and stimulate cell growth and plant biomass. Plant growth-promoting rhizobacteria (PGPR) carry out numerous mechanisms that enhance growth in seedlings, such as nutrient solubilization, phytohormone production, biocontrol activity, and regulation of induced systemic resistance (ISR) and acquired systemic resistance (ASR). Bacillus paralicheniformis TRQ65 is a biological and plant growth-promoting bacterium isolated from wheat (Triticum turgidum subsp. durum) rhizosphere. In this study, we performed a transcriptomic analysis of wheat seedlings inoculated with the native rhizobacterium Bacillus paralicheniformis TRQ65 (1 × 10⁷ cells∙g ^-1 of soil) at early development stages (GS15). A morphometrical assay was carried out to confirm growth promotion and after the cultivation period, TRQ65 was re-isolated to define inoculum persistence. Inoculated seedlings showed a significant (P < 0.05) increase in shoot length (93.48%) and dry weight in both shoot (117.02%) and root (48.33%) tissues; also, the strain persisted in the soil at 1.4 × 10⁷ UFC∙g^-1 of soil. A total of 228 differentially expressed genes (DEGs) (FDR < 0.05 and |log2 fold change|≥ 1.3) were observed in response to TRQ65 inoculation, of which 185 were down-regulated and 43 were up-regulated. The transcriptional patterns were characterized by the regulation of multidimensional cell growth (ROS, Ca⁺² channel, and NADPH oxidases activity), suppression of defense mechanism (PR proteins, PDFs, ROS, transcription factors), induction of central stimuli receptors (RALF, WAK, MAPK), carbohydrate metabolism (invertase activity) and phytohormone-related transport (ABCG transporter and AAAP). These results suggest that B. paralicheniformis TRQ65 is a promising bioinoculant agent for increasing wheat growth and development by reprogramming ISR and ASR simultaneously, suppressing defense mechanisms and inducing central stimuli response.

Transcriptional Regulation of Metabolic and Cellular Processes in Durum Wheat (Triticum turgidum subsp. durum) in the Face of Temperature Increasing

The Yaqui Valley, Mexico, has been historically considered as an experimental field for semiarid regions worldwide since temperature is an important constraint affecting durum wheat cultivation. Here, we studied the transcriptional and morphometrical response of durum wheat at an increased temperature (+2 °C) for deciphering molecular mechanisms involved in the thermal adaptation by this crop. The morphometrical assay showed a significant decrease in almost all the evaluated traits (shoot/root length, biovolume index, and dry/shoot weight) except in the dry root weight and the root:shoot ratio. At the transcriptional level, 283 differentially expressed genes (DEGs) were obtained (False Discovery Rate (FDR) ≤ 0.05 and |log2 fold change| ≥ 1.3). From these, functional annotation with MapMan4 and a gene ontology (GO) enrichment analysis with GOSeq were carried out to obtain 27 GO terms significantly enriched (overrepresented FDR ≤ 0.05). Overrepresented and functionally annotated genes belonged to ontologies associated with photosynthetic acclimation, respiration, changes in carbon balance, lipid biosynthesis, the regulation of reactive oxygen species, and the acceleration of physiological progression. These findings are the first insight into the regulation of the mechanism influenced by a temperature increase in durum wheat.

Quantitative microbial risk assessment of Cryptosporidium and Giardia in well water from a native community of Mexico

Cryptosporidium and Giardia are gastrointestinal disease-causing organisms transmitted by the fecal-oral route, zoonotic and prevalent in all socioeconomic segments with greater emphasis in rural communities. The goal of this study was to assess the risk of cryptosporidiosis and giardiasis of Potam dwellers consuming drinking water from communal well water. To achieve the goal, quantitative microbial risk assessment (QMRA) was carried out as follows: (a) identification of Cryptosporidium oocysts and Giardia cysts in well water samples by information collection rule method, (b) assessment of exposure to healthy Potam residents, (c) dose-response modelling, and (d) risk characterization using an exponential model. All well water samples tested were positive for Cryptosporidium and Giardia. The QMRA results indicate a mean of annual risks of 99:100 (0.99) for cryptosporidiosis and 1:1 (1.0) for giardiasis. The outcome of the present study may drive decision-makers to establish an educational and treatment program to reduce the incidence of parasite-borne intestinal infection in the Potam community, and to conduct risk analysis programs in other similar rural communities in Mexico.

Microbiological water quality in a large irrigation system: El Valle del Yaqui, Sonora México

The primary objective of this study was to determine the microbial water quality of a large irrigation system and how this quality varies with respect to canal size, impact of near-by communities, and the travel distance from the source in the El Valle del Yaqui, Sonora, México. In this arid region, 220,000 hectares are irrigated with 80% of the irrigation water being supplied from an extensive irrigation system including three dams on the Yaqui River watershed. The stored water flows to the irrigated fields through two main canal systems (severing the upper and lower Yaqui Valley) and then through smaller lateral canals that deliver the water to the fields. A total of 146 irrigation water samples were collected from 52 sample sites during three sampling events. Not all sites could be accessed on each occasion. All of the samples contained coliform bacteria ranging from 1,140 to 68,670 MPN/100 mL with an arithmetic mean of 11,416. Ninety-eight percent of the samples contained less than 1,000 MPN/100 mL Escherichia coli, with an arithmetic mean of 291 MPN/100 mL. Coliphage were detected in less than 30% of the samples with an arithmetic average equal to 141 PFU/100 mL. Enteroviruses, Cryptosporidium oocysts, and Giardia cysts were also detected in the canal systems. No significant difference was found in the water quality due to canal system (upper or lower Yaqui Valley), canal-size (main vs. lateral), distance from source, and the vicinity of human habitation (presence of various villages and towns along the length of the canals). There was a significant decrease in coliforms (p < 0.011) and E. coli (< 0.022) concentrations as travel distance increased from the City of Obregón.