Proteins are the major constituents of muscle and are key molecules regulating the metabolic changes during conversion of muscle to meat. Brazil is one of the largest exporters of beef and most Brazilian cattle are composed by zebu (Nellore) genotype. Bos indicus beef is generally leaner and tougher than Bos taurus such as Angus. The aim of this study was to compare the muscle proteomic and phosphoproteomic profile of Angus and Nellore. Seven animals of each breed previously subjected the same growth management were confined for 84 days. Proteins were extracted from Longissimus lumborum samples collected immediately after slaughter and separated by two-dimensional electrophoresis. Pro-Q Diamond stain was used in phosphoproteomics. Proteins identification was performed using matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Tropomyosin alpha-1 chain, troponin-T, myosin light chain-1 fragment, cytoplasmic malate dehydrogenase, alpha-enolase and 78 kDa glucose-regulated protein were more abundant in Nellore, while myosin light chain 3, prohibitin, mitochondrial stress-70 protein and heat shock 70 kDa protein 6 were more abundant in Angus (P<0.05). Nellore had higher phosphorylation of myosin regulatory light chain-2, alpha actin-1, triosephosphate isomerase and 14-3-3 protein epsilon. However, Angus had greater phosphorylation of phosphoglucomutase-1 and troponin-T (P<0.05). Therefore, proteins involved in contraction and muscle organization, myofilaments expressed in fast or slow-twitch fibers and heat shock proteins localized in mitochondria or sarcoplasmic reticulum and involved in cell flux of calcium and apoptosis might be associated with differences in beef quality between Angus and Nellore. Furthermore, prohibitin appears to be a potential biomarker of intramuscular fat in cattle. Additionally, differences in phosphorylation of myofilaments and glycolytic enzymes could be involved with differences in muscle contraction force, susceptibility to calpain, apoptosis and postmortem glycolysis, which might also be related to differences in beef quality among Angus and Nellore.

Attack by herbivores is a major biotic stress limiting the soybean crop production. Plant defenses against caterpillars include the production of secondary metabolites such as flavonoids, which constitute a diverse group of plant secondary metabolites. Thus, a more discriminate metabolic profiling between genotypes are important for a more comprehensive and reliable characterization of soybean resistance. Therefore, in this study a non-targeted LC/MS-based for analysis of flavonoid profiles of soybean genotypes contrasting to the resistance to A. gemmatalis was applied. Clustering analysis revealed profiles highly distinct between the susceptible UFV 105 AP and the resistant IAC 17 genotypes. This comparative approach enables to identify directly from leaf extract some new compounds related to resistance, some of which were present in higher abundance specifically in the IAC 17 genotype: four Quercetin conjugates, Rutin (Quercetin 3-O-Rutinoside), Quercetin-3,7-O- di-glucoside, Quercetin-3-O-rhamnosylglycoside-7-O-glucoside and Quercetin-3-O-rhamnopyranosyl-glucopyranoside-rhamnopyranoside; two Genistein conjugates, Genistein-7-O-diglucoside-dimalonylated and Genistein-7-O-6-O-malonylglucoside; and one Daidzein conjugate, Daidzein-7-O-Glucoside-malonate. The most abundant flavonoid glycoconjugates in soybean leaves belongs to Quercetin and Kaempferol classes. However, only one from the identified compounds was classified as a Kaempferol. The Kaempferol-3-O-L-rhamnopyranosyl-glucopyranoside showed high abundance in the resistant genotype IAC 17. The metabolic profiles generated by LC/MS allowed the reconstruction of the flavonoid biosynthetic pathways, which revealed a constitutive character for herbivory resistance in the resistant genotype IAC-17 and a metabolic regulation for the rechanneling of Quercetin, Kaempferol and Genistein conjugates in soybean. Highest relative abundances were detected for glyconjugates, such as Rutin, Quercetin 3-O-rhamnosylglycoside-7-O-glucoside and Quercitin-3-O-rhamnopyranosyl-glucopyranoside-rhamnopyranoside in the leaves of the resistant genotype.

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In addition to playing a key role in the response to environmental changes, cell walls are also considered as a valuable feedstock for cellulosic ethanol. Here we explored the effects of the stress-response hormones, salicylic acid and methyl jasmonate, on cell wall biosynthesis and biomass digestibility in Brachypodium distachyon, a species recently considered as a suitable model for biomass conversion. We found that in response to salicylic acid or methyl jasmonate treatment, plant growth was reduced coupled with significant changes in cell wall composition. Cellulose content increased in response to methyl jasmonate whereas a reduction in lignin content was found after salicylic acid application. Moreover, hemicellulose composition was altered and increases in caffeic acid, ferulic acid and p-coumaric acid content were detected in response to both treatments. The hormonal profile and the expression pattern of genes involved in cell wall biosynthesis were also modified. Biomass digestibility was reduced in leaf tissue after salicylic acid treatment and was negatively correlated with ferulic acid and p-coumaric acid content. The results obtained here aid in our understanding of cell wall dynamics in response to stress and will enable the development of new strategies to improve cell wall digestibility in bioenergy feedstock.

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Soybean is one of most consumed and produced grains in the world, and Anticarsia gemmatalis is a pest that causes great damage to this crop due to severe defoliation during its larval phase. Plants have mechanisms that lead to the inhibition of proteases in the intestine of these herbivores, hampering their development. Understanding this complex protease inhibitor is important for pest control. The objective of this study was to evaluate the enzymatic profiles of the intestinal proteases of the soybean caterpillar at different instars. For this, the proteolytic profile of the gut in the third, fourth, and fifth instars were analyzed.Irreversible inhibitors of proteases were separately incubated with A. gemmatalis enzyme extracts at the third, fourth, and fifth instar to assess the contribution of these proteases to total proteolytic activity. The enzymatic extracts were also evaluated with specific substrates to confirm changes in the specific activities of trypsin-like, chymotrypsin-like, and cysteine proteases at different instars. The results showed that the protease profile of A.gemmatalis gut changes throughout its larval development.The activity of cysteine proteases was more intense in the first instar. On the contrary, the serine proteases The protease profile of the gut of A. gemmatalis changes throughout larval development. In the third instar, cysteine protease activity is predominant over others. In the fourth and fifth instars, proteolytic activity is mainly due to serine proteases. This difference in activity in the different instars of A. gemmatalis suggests that the expression of the genes coding for proteases also changes throughout the development of the insect. Using serine PIs is a good strategy for controlling insect pests, as these are the main proteolytic enzymes of Lepidoptera. However, the presence of other important protease subclasses in insect digestibility suggests that a combination of serine and cysteine PIs may be promising, aiming to compromise larval development at different instars.