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Hot water treatment (HWT) of tomato (Solanum lycopersicum L.) fruit reduces the symptoms of chilling injury (CI). The aim of this study was to identify metabolites associated with HWT-induced CI tolerance in tomato fruit cv. Imperial. Mature green tomatoes with HWT (42°C/5 min) and control were stored under chilling conditions (5°C/20 days) and then ripened (21°C/7 days). Methanol extracts from pericarp were analyzed for total phenolics (TP), antioxidant activity (AoxA), and metabolic profiling by UPLC-DAD-MS and GC-MS. After cold storage and ripening, HWT fruit showed less CI, higher TP, and AoxA than control. It also showed an increased accumulation of phenolics, sugars, and some alkaloids that may be mediated by azelaic acid, glutamine, and tryptophan. The levels of N-feruloyl putrescine, esculeoside AII, and hydroxy-α-tomatine II were reduced. The better metabolic performance of HWT fruit under cold storage was associated with a higher accumulation of several metabolites (e.g., antioxidants and osmolytes) in ripening fruit. PRACTICAL APPLICATION: The identification of metabolites associated with the reduction of chilling injury (CI) symptoms in HWT tomato fruit extends the understanding of the mechanisms involved in CI tolerance. This information provides targets that could be used to develop strategies for preventing CI (e.g., genetic improvement of tomato, direct application of key metabolites). The application of such strategies will increase the economic value and decrease postharvest losses.

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a major pest of the tomato (Solanum lycopersicum L.) crop worldwide, mostly because of resistance to insecticide that has been associated with endosymbionts. Although knowledge of biotypes in the B. tabaci complex and its endosymbionts is critical for developing pest management strategies, limited information is available on the pest in the Culiacan Province of Mexico. In total, 249 samples of whiteflies were collected from tomato plants of four growers in the Culiacan Valley to analyze the genetic identity of the B. tabaci complex and its endosymbionts. PCR and phylogenetic analyses on the mitochondrial cytochrome oxidase I gene (mtCO1) revealed MEAM1, MED, and indigenous genetic groups in 53, 19, and 28%, respectively, of B. tabaci on tomatoes. Individual whiteflies were examined for endosymbionts through specific primers and phylogenetic analyses on the 16S rRNA and the 23S rRNA genes. Incidence of Portiera, Hamiltonella, Rickettsia, Wolbachia, and Cardinium was 81, 46, 28, 9, and 13%, respectively, in the B. tabaci samples analyzed. A new bacterium-endosymbiont in the genus Orientia was found and described in 63% of the samples of B. tabaci. A mixture of the endosymbionts Rickettsia+UAS_511+Cardinium was observed in 10% of samples of B. tabaci MED, while in the MEAM1 biotype, a combination of Hamiltonella+UAS_511 was in 32% of the samples analyzed. The study highlights the diversity and distribution of B. tabaci and its endosymbionts throughout the Culiacan Province and provides evidence for control of the insect pest.

Chickpea (Cicer arietinum L.) genotypes, nine kabuli from Mexico and 9 desi from other countries, were investigated for their phenolic profiles and antioxidant activity (AA). Phenolics in methanol extracts (ME) were analyzed by ultra-performance liquid chromatography coupled to diode array detection and mass spectrometry (UPLC-DAD-MS), whereas the AA was measured as Trolox equivalents (TE) by ABTS, DPPH and FRAP methods. Twenty phenolic compounds were identified in the ME and their levels showed a great variability among the chickpea genotypes. Phenolic acids and flavonoids were the most abundant compounds in kabuli and desi genotypes, respectively. The AA values (μmol TE/ 100 g dw) by ABTS (278-2417), DPPH (52-1650), and FRAP (41-1181) were mainly associated with the content of sinapic acid hexoside, gallic acid, myricetin, quercetin, catechin, and isorhamnetin, suggesting they are the main compounds responsible for the AA. The sum of the AA obtained for standards of these compounds evaluated at the concentration found in the extracts accounted for 34.3, 69.8, and 47.0% of the AA in the extract by ABTS, DPPH, and FRAP, respectively. In the AA by DPPH, most of the mixtures of these compounds resulted in synergistic interactions. Three desi genotypes with black seeds (ICC 4418, ICC 6306, and ICC 3761) showed the highest AA and flavonoids content, whereas the most promising kabuli genotypes were Surutato 77, Bco. Sin. 92, and Blanoro that showed the highest values of phenolic acids. These genotypes represent good sources of antioxidants for the improvement of nutraceutical properties in chickpea.

Candidatus Liberibacter solanacearum (CLs) es una bacteria asociada a la enfermedad “Permanente del Tomate” (PT) que ocasiona grandes daños a la producción de tomate (Solanum lycopersicum L.) en México. El uso de genotipos resistentes es la alternativa más sustentable para el manejo de enfermedades en plantas; sin embargo, actualmente no hay reportes de cultivares comerciales de tomate resistentes a CLs. Por lo anterior, el objetivo del presente estudio fue evaluar la respuesta a la infección con CLs en los cultivares Río Grande®, Moctezuma®, Marmande, DRK2180®, La Roca®, Bonny Best® y la línea avanzada UAS 2016. La evaluación se desarrolló en Culiacán, Sinaloa, México en condiciones de invernadero mediante un diseño de bloques completos al azar con cuatro repeticiones. La inoculación de CLs se llevó a cabo mediante su vector y la expresión de la enfermedad en la planta se registró durante siete semanas. La variabilidad genética de los genotipos fue analizada con el empleo de 15 microsatélites (SSR). Los resultados indicaron que la expresión de PT en UAS 2016 y Marmande fue significativamente menor que en Río Grande® y Moctezuma®, sin que DRK2180®, La Roca® y Bonny Best® mostraran diferencia significativa con respecto a esta última variedad. La diversidad genética total presentó un valor de 0.58 y un GST de 0.30, lo que indica que los genotipos presentaron variabilidad genética similar.

Hot water (HW) pre-treatment provides tolerance to chilling injury (CI) in tomato fruit, but little is known about the biochemical bases of this tolerance. The aim of this study was to identify proteins associated with CI tolerance in HW pre-treated tomato cv. Imperial. We used a comparative proteomic analysis between HW-treated (42 °C, 5 min) and non-treated fruit after cold storage (0, 10, and 20 days at 5 °C) and ripening (7 days at 21 °C); as well as real-time PCR to analyze the expression of genes encoding some selected proteins. Thirteen proteins were differentially expressed after 20 days of cold storage and 13 after the subsequent ripening period; polypeptides showing greater accumulation in HW-treated fruit included small heat shock proteins, antioxidant enzymes (thioredoxin peroxidase 1, superoxide dismutase, and ascorbate peroxidase), plant defense proteins (PR-10 and remorin 1) and RNA-binding chaperone protein (GR-RBP). In addition, non-treated fruit showed higher expression of enzymes involved in detoxification, carbohydrate, and energy metabolism, suggesting a low cellular efficiency in energy production due to severe structural damage. The hot water-induced chilling tolerance in tomato fruit appears to be related with the prevention of protein denaturation, activation of the antioxidant and defense systems, and the potential regulation of cold sensitive genes.

Pineapple slices were treated with three antioxidants and stored under passive modified atmosphere packaging (MAP) to evaluate the effect of these treatments on tissue browning (percentage of dark area) and the accumulation of ascorbic acid and total phenolics. Pineapple slices were immersed in ascorbic acid (AA), isoascorbic acid (IAA), and N-acetylcysteine (NAC) solutions for 2 min, and then were packed and stored at 5 °C under air (AIR) or MAP for 15 days. Water was used as control. The application of IAA and NAC under passive MAP reduced better the tissue browning index and maintained a good quality of the slices. The use of AA and IAA increased the contents of ascorbic acid and total phenolics. The application of IAA followed by storage under MAP conditions was effective in reducing tissue browning, which was associated with a higher retention of ascorbic acid and total phenolics contents of the pineapple slices.

Spent coffee grounds (SCG) are residues generated during coffee beverage preparation that contain 12–17% protein and are a rich source of peptides. Bacteria can generate peptides with potential bioactivity through protein hydrolysis in a fermentation process. This study aimed to obtain digested protein hydrolysates with potential bioactivity from Bacillus clausii-fermented SCG. The fermentation was performed with 1.5 × 108 colony-forming units/mL of bacteria at 37 °C for 39 h. Total and soluble proteins and protein hydrolysates were quantified using spectrophotometric techniques. Pepsin/pancreatin protein hydrolysates were characterized using ultra-performance liquid chromatography-mass spectrometry. The physicochemical properties and potential bioactivity of peptides were evaluated using in silico analysis. The fermentation process increased the amounts of total proteins, soluble proteins, and protein hydrolysates by 2.7, 2.2, and 1.2-fold, respectively, compared to non-fermented SCG. Fermented SCG samples, increased the abundance of seven peptides that displayed potentially antioxidant capacity, angiotensin-converting enzyme activity, and dipeptidyl peptidase-IV-inhibitor activity. The YGF and GMCC peptide sequences presented the highest bioactivity scores (0.97 each), followed by the YWRYDCQ (0.65) and RMYRY (0.60) peptides. In summary, fermented SCG had increased abundance of peptides with high bioactive potential that may be exploited in managing oxidative stress, hypertension, and diabetes.

The application of a quarantine hot water treatment (HWT) induces chilling injury (CI) tolerance in mango fruit, but little is known about the mechanisms involved in this tolerance. The aim of this study was to identify metabolomic changes associated with HWT-induced CI tolerance in 'Keitt' mango fruit. Mature green fruit treated with hot water (HWT; 46.1 °C, 75-90 min) and non-treated (control) were stored for 20 d at 5 °C and ripened for 7 d at 21 °C. The incidence of chilling injury symptoms was registered as CI index. Methanol extracts of fruit peels were used for comparative metabolomics analyses by UPLC-DAD-MS and GC-MS. Total phenolics (TP) were analyzed by the Folin-Ciocalteu assay and the antioxidant activity (AA) was measured by ABTS, DPPH, and FRAP methods. HWT provided CI tolerance to mango fruit as evidenced by a low incidence of symptoms. Fifty-two and 14 metabolites were identified by UPLC-DAD-MS and GC-MS, respectively. These metabolites were classified as galloylquinic acids, gallic acid esters, gallotannins, gallic acid derivatives, benzophenone derivatives, xanthones, flavonoids, organic acids, sugars, fatty acids, and other metabolites (myo-inositol). The HWT before cold storage increased the abundance of galloylquinic acids, gallic acid esters, gallotannins, quercetin 3-O-rhamnoside, and myo-inositol; and it decreased the levels of mangiferin, ribose, malic acid, and palmitic acid. After cold storage and ripening, HWT fruit maintained higher levels of galloylquinic acids, gallic acid esters, gallotannins, quercetin 3-O-rhamnoside, mangiferin, myo-inositol, linolenic acid, and sugars than those in control fruit. HWT fruit also had higher values of TP and AA by the three methods. Control fruit had higher levels of citric acid, malic acid, palmitic acid, and ribose, as well as lower unsaturated/saturated fatty acid ratio. The HWT-induced CI tolerance in mango fruit appears to be associated with an increased content of antioxidants and osmoprotectant metabolites and a higher ratio of unsaturated/saturated fatty acids.

The variability in grain and starch characteristics and their relationship with the accumulation of starch granule associated proteins were investigated in five maize landraces of Northwest Mexico (Blando de Sonora, Chapalote, Elotero de Sinaloa, Reventador, and Tabloncillo). Significant differences were observed in grain hardness related traits, starch physicochemical properties, and structural properties. Blando de Sonora showed very soft grains, whereas the hardest grains were observed for Chapalote and Reventador. Starch granules isolated from landraces with hard grains contained more amylose and showed polygonal shapes, lower crystallinity and enthalpy of gelatinization, and greater retrogradation and proportion of long amylopectin chains. Proteomic analysis identified the enzymes granule-bound starch synthase I (GBSSI), starch synthase I and IIa, starch branching enzyme IIb, sucrose synthase 1, and pyruvate phosphate dikinase 2 as granule-associated proteins. The abundance of GBSSI correlated signif...

The use of whey as a natural culture medium to produce hydrolysates with antimicrobial from Bacillus clausii is the objective of this research. The fermentation process was carried out at 25 ℃ for five days, where proteolytic activity, soluble peptides quantification, and antimicrobial activity using the disc diffusion method were determined every day. The fermented whey reached values ​​of proteolytic activity between 90 and 260 U ml

Genetic analysis using quality protein maize (QPM) recombinant inbred lines derived from K0326Y QPM and W64Ao2 identified three quantitative trait loci (QTL) in bins 1.06, 7.02 and 9.03 associated with opaque2 endosperm modification. We evaluated the effects of these QTLs on protein accumulation and starch physicochemical properties. The QTL in bin 1.06 is close to α-zein genes, and vitreous individuals with this QTL had increased accumulation of 19-kDa α-zein, 27-kDa γ-zein and legumin-1. The QTL in bin 7.02 corresponds to the γ-zein locus, and greater accumulation of this protein was found in vitreous individuals. The QTL in bin 9.03 is close to starch biosynthetic genes; greater accumulation of granule-bound starch synthase and amylose was observed in vitreous kernel samples with this locus and that in bin 1.06, as well as less gelatinization enthalpy and crystallinity. Vitreous kernels contained angular-shaped/compact starch granules and more short-intermediate length chains of amylopectin. These results support that endosperm modification in QPM is associated with increased accumulation of γ-zein and other storage proteins, but also show that synthesis of less crystalline starch with more amorphous regions at the periphery of granules, which favor their packing and association with endosperm proteins, may also be an important factor.

In the state of Sinaloa Mexico, traditional farmers still cultivate maize accessions with a wide diversity of morphological characteristics, but the gene reservoir maintained in these populations has been poorly studied and it is being lost due to changes in land use and the adoption of hybrid commercial varieties. The aim of this study was to evaluate the genetic diversity of some of these maize populations to contribute to their preservation. Twenty eight accessions were used for the analysis. DNA was extracted from 396 individuals and probed with 20 microsatellites distributed across the maize genome. A total of 121 alleles were obtained (average of 6.1 alleles per locus) and a total genetic diversity of 0.72. The UPGMA-cluster analysis, model-based population structure and principal component analysis revealed three major groups, one formed mainly by accessions of races typical of the Northwestern lowlands (Chapalote, Dulcillo del Noroeste, Tabloncillo Perla, Blando de Sonora and Elotero de Sinaloa) and the other two with accessions mainly from Tabloncillo and Tuxpeno. The high number of alleles per locus and total genetic diversity found in this study demonstrate a broad genetic basis of the accessions of maize landraces from Sinaloa, representing a gene reservoir useful in breeding programs.

The opaque2 (o2) mutation in maize (Zea mays L.) increases the content of free amino acids (FAA) in the endosperm. We investigated the basis of this trait by using recombinant inbred lines from a cross of Oh545o2 (high FAA) and Oh51Ao2 (low FAA) to identify quantitative trait loci (QTL) for FAA content and to determine their effect on FAA composition and protein accumulation. Mapping identified six QTLs that accounted for 71% of the phenotypic variation. Two QTLs in bins 4.01 and 7.02 are close to α-zein genes; high FAA individuals with these QTLs had reduced accumulation of α-zein 19 kDa isoforms and increased FAA abundant in α-zeins. A QTL in bin 3.03 is close to a gene encoding triose phosphate isomerase (tpi4) and a higher expression of this enzyme was found in high FAA individuals. Other differentially expressed proteins included vicilin-like globulins and the enzymes glyceraldehyde-3-phosphate dehydrogenase, enolase-2, sorbitol dehydrogenase and granule-bound starch synthase. The results suggest that the increased levels of FAA in o2 endosperm are mainly due to the reduction of storage proteins and the failure to incorporate their amino acids into other proteins, as well as the alteration of carbohydrate metabolism that may favor amino acid biosynthesis.