Cowpea-Meloidogyne incognita interaction: Root proteomic analysis during early stages of nematode infection.

Cowpea (Vigna unguiculata L. Walp) is an important legume species well adapted to low fertility soils and prolonged drought periods. One of the main problems that cause severe yield losses in cowpea is the root-knot nematode Meloidogyne incognita. The aim of this work was to analyze the differential expression of proteins in the contrasting cultivars of cowpea CE 31 (highly resistant) and CE 109 (slightly resistant) during early stages of M. incognita infection. Cowpea roots were collected at 3, 6, and 9 days after inoculation and used for protein extraction and 2-DE analysis. From a total of 59 differential spots, 37 proteins were identified, mostly involved in plant defense, such as spermidine synthase, patatin, proteasome component, and nitrile-specifier protein. A follow-up study was performed by quantitative RT-PCR analysis of nine selected proteins and the results revealed a very similar upregulation trend between the protein expression profiles and the corresponding transcripts. This study also identified ACT and GAPDH as a good combination of reference genes for quantitative RT-PCR analysis of the pathosystem cowpea/nematode. Additionally, an interactome analysis showed three major pathways affected by nematode infection: proteasome endopeptidase complex, oxidative phosphorylation, and flavonoid biosynthesis. Taken together, the results obtained by proteome, transcriptome, and interactome approaches suggest that oxidative stress, ubiquitination, and glucosinolate degradation may be part of cowpea CE 31 resistance mechanisms in response to nematode infection.

Effects of acute exercise over heart proteome from monogenic obese (ob/ob) mice.

Exercise is recognized to prevent and attenuate several metabolic and cardiovascular disorders. Obesity is commonly related to cardiovascular diseases, frequently resulting in heart failure and death. To elucidate the effects of acute exercise in heart tissue from obese animals, 12-week-old C57BL6/J obese (ob/ob) and non-obese (ob/OB) mice were submitted to a single bout of swimming and had their hearts analyzed by proteomic techniques. Mice were divided into three groups: control (ob/ob, n = 3; ob/OB, n = 3); a moderate intensity consisting of 20 min of swimming around 90% of Maximal Lactate Steady State (ob/ob, n = 3; ob/OB, n = 3), and a high intensity exercise performed as an incremental overload test (ob/ob, n = 3; ob/OB, n = 3). Obesity modulations were analyzed by comparing ob/ob and ob/OB control groups. Differential 2-DE analysis revealed that single session of exercise was able to up-regulate: myoglobin (ob/ob), aspartate aminotransferase (ob/OB) and zinc finger protein (ob/OB) and down-regulate: nucleoside diphosphate kinase B (ob/OB), mitochondrial aconitase (ob/ob and ob/OB) and fatty acid binding protein (ob/ob). Zinc finger protein and α-actin were up-regulated by the effect of obesity on heart proteome. These data demonstrate the immediate response of metabolic and stress-related proteins after exercise so as contractile protein by obesity modulation on heart proteome.

Identification of proteins in susceptible and resistant Brassica oleracea responsive to Xanthomonas campestris pv. campestris infection.

UNLABELLED: Cruciferous plants are important edible vegetables widely consumed around the world, including cabbage, cauli-flower and broccoli. The main disease that affects crucifer plants is black rot, caused by Xanthomonas campestris pv. campestris (Xcc). In order to better understand this specific plant-pathogen interaction, proteins responsive to Xcc infection in resistant (União) and susceptible (Kenzan) Brassica oleracea cultivars were investigated by 2-DE followed by mass spectrometry. A total of 47 variable spots were identified and revealed that in the susceptible interaction there is a clear reduction in the abundance of proteins involved in energetic metabolism and defense. It was interesting to observe that in the resistant interaction, these proteins showed an opposite behavior. Based on our results, we conclude that resistance is correlated with the ability of the plant to keep sufficient photosynthesis metabolism activity to provide energy supplies necessary for an active defense. As a follow-up study, qRT-PCR analysis of selected genes was performed and revealed that most genes showed an up-regulation trend from 5 to 15days after inoculation (DAI), showing highest transcript levels at 15DAI. These results revealed the gradual accumulation of transcripts providing a more detailed view of the changes occurring during different stages of the plant-pathogen interaction. BIOLOGICAL SIGNIFICANCE: In this study we have compared cultivars of Brassica oleracea (cabbage), susceptible and resistant to black rot, by using the classical 2-DE approach. We have found that resistance is correlated with the ability of the plant to keep sufficient photosynthesis metabolism activity to provide energy supplies necessary for an active defense.

Proteomic analysis of upland rice (Oryza sativa L.) exposed to intermittent water deficit.

Rice is the most important crop consumed all over the world. In Brazil, irrigated rice covers 50 % of the rice producing area and is responsible for 75 % of the national production. Upland rice covers most of the remaining area, and is therefore, a very important production system in the country. In the present study, we have used the drought tolerant upland rice variety Três Meses Antigo to investigate the proteomic changes that occur during drought stress. Plants were submitted to drought by the reposition of 50 % of the water lost daily. Twenty days after the beginning of the drought stress period, leaves were harvested and used for protein extraction. The 2D maps obtained from treated and control plants revealed 408 reproducible spots, 44 of which were identified by mass spectrometry, including 15 differential proteins. Several unaltered proteins were also identified (39 spots) and were mainly involved in photosynthesis. Taken together, the results obtained suggest that the tolerant upland rice up-regulates anti-oxidant and energy production related proteins in order to cope with water deficit.