Rôle des facteurs de transcription CBF dans le contrôle du développement de l'eucalyptus en condition de stress

Eucalyptus, feuillu le plus planté dans le monde, est fortement exposé au froid en raison de l'absence de dormance. Les facteurs de transcription CBF (CRT-binding Factor) jouent un rôle important dans la réponse aux stress abiotiques, particulièrement au froid. Préalablement à mes travaux, 17 gènes CBF avaient été identifiés chez E. grandis. Une étude fonctionnelle par surexpression de gènes CBF chez un hybride d'E. urophylla x E. grandis avait été initiée avec un phénotypage des lignées transgéniques au stade microboutures. Mon travail s'est articulé autour d'une étude in silico du régulon potentiel des CBF et de la caractérisation des sur-exprimants CBF après les avoir enracinés puis acclimatés ex vitro. Les résultats obtenus mettent en évidence de profondes modifications dans la tolérance, la croissance, la morphologie et l'anatomie des transformants qui, le plus souvent, ont pu être reliées à la surexpression de gènes impliqués dans ces processus. Au-delà d'un impact sur les feuilles, ces travaux suggèrent fortement pour la première fois un contrôle très important des CBF sur la formation de la tige.Eucalyptus, the most widely planted hardwood in the world, is highly exposed to the cold due to the lack of dormancy. CBF transcription factors play an important role in the response to abiotic stress, particularly cold stress. Previously, 17 CBF genes have been identified in E. grandis and a functional study of CBF genes by overexpressing in a hybrid E. urophylla x E. grandis has been initiated through the phenotyping of transgenic lines at microcutting stage. My work involved in silico study of the potential CBF regulon and the characterization of these transformants after rooting and ex vitro acclimatization. The results show substantial changes in tolerance, growth, morphology and anatomy of transformants which most oftent could be associated to the overexpression of genes involved in the corresponding process. Beyond the impact on the leaves, this work strongly suggests for the first time a very important control of CBF on stem formation

Growth and quality of hydroponic cultivated spinach (Spinacia oleracea L.) affected by the light intensity of red and blue LEDs

This study aimed to evaluate the effect of four light intensities (90, 140, 190 and 240 μmol m-2 s-1) provided by red-blue LED light (spectrum ratio: R660/B450 = 4/1) on the growth and quality of hydroponic cultivated spinach. The results showed that when the light intensity increased, plant height, leaf number, root length, leaf width, shoot fresh weight, shoot dry weight, root fresh weight and root dry weight were increased but specific leaf weight and shoot-to-root ratio did not increase. The highest values of growth parameters were observed under 190 μmol m-2 s-1 treatment, while the lowest values were observed under 90 μmol m-2 s-1 treatment. At higher light intensities, K+, oxalic acid and nitrate contents tended to decrease but not Ca2+ content. Meanwhile, the highest values of Fe2+, crude fiber, soluble-solids, total polyphenol and vitamin C contents were observed under 190 μmol m-2 s-1 treatment, but 190 μmol m-2 s-1 treatment showed the lowest organic acid content. Our results indicated that among all experimental lighting treatments, 190 μmol m-2 s-1 light intensity showed the best effect on the growth and quality of hydroponic cultivated spinach

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Vietnam PHÂN TÍCH in silico CÁC GENE MÃ HÓA PROTEIN SWEET Ở CÂY DỀN LẤY HẠT (Amaranthus hypochondriacus L.)

SWEET (Sugars Will Eventually be Exported Transporter) is one of the essential protein families transporting sugar in plants. In this study, 20 genes encoding the SWEET proteins were identified from the grain aramanth (Amaranthus hypochondriacus L.) genome and analyzed. The genomic full-length of these genes ranges from 729 to 9324 nucleotides, most of which have four or five introns. The predicted proteins have 226 to 311 amino acids and possess six or seven conserved transmembrane helix regions. Most of these proteins are alkaline, with pI 8.08–9.73. Analysing the phylogeny, we can classify SWEETs of Amaranthus hypochondriacus L. (AhSWEET) into four groups: group I (three genes), group II (seven genes), group III (eight genes), and group IV (two genes). These genes are not equally distributed in the grain aramanth genome. Ten gene duplication events were detected, forming the duplicated SWEET gene pairs, including nine WD events. The duplicated gene pairs are affected by the purifying selection. which stabilizes the coding sequences of these genes. This result is a basis for further studies, such as gene function or genetic modification using SWEET genes.SWEET (Sugars Will Eventually be Exported Transporter) là một trong các họ protein có chức năng vận chuyển đường quan trọng ở thực vật. Trong nghiên cứu này, 20 gene mã hóa các protein SWEET trong hệ gene cây dền lấy hạt (Amaranthus hypochondriacus L.) đã được xác định và phân tích. Chiều dài các gene này dao động từ 729 đến 9324 nucleotide và hầu hết gene có bốn hoặc năm intron. Các protein suy diễn có chiều dài từ 226 tới 311 amino acid và mang sáu hoặc bảy xoắn xuyên màng đặc trưng. Hầu hết các protein này có tính kiềm với pI 8,08–9,73. Phân tích cây phả hệ cho phép phân chia các AhSWEET thành bốn nhóm, nhóm I (ba gene), nhóm II (bảy gene), nhóm III (tám gene) và nhóm IV (hai gene). Các gene này phân bố không đồng đều trong hệ gene của cây dền lấy hạt. Mười hiện tượng nhân gene đã được phát hiện hình thành nên các cặp gene SWEET lặp ở loài cây này, trong đó chủ yếu là hiện tượng nhân gene trên toàn hệ gene. Các gene lặp trong cặp hình thành từ quá trình nhân gene chịu sự tác động của chọn lọc âm, giữ ổn định trình tự nucleotide. Kết quả của nghiên cứu này là cơ sở cho các nghiên cứu xa hơn như nghiên cứu chức năng gene hoặc cải tiến di truyền

ẢNH HƯỞNG CỦA BA DUNG DỊCH DINH DƯỠNG HOAGLAND, TC MOBI VÀ KNOP ĐẾN SINH TRƯỞNG, NĂNG SUẤT VÀ CHẤT LƯỢNG QUẢ CỦA CÂY CÀ CHUA CHANOKA F1 THỦY CANH

The nutrient solution is an important factor which directly affects the growth, yield, and quality of hydroponic crops. In this study, the effects of three common nutrient solutions, namely Hoagland, Knop and TC Mobi on the growth, yield, and fruit quality of tomato Chanoka F1 variety were evaluated. The results showed that the Hoagland solution had more positive influence on the growth, yield and fruit quality characteristics of tomato Chanoka F1 than the other two solutions. The plants grown in the Knop solution had the smallest yield and the poorest fruit quality. In addition, the nitrate content in the fruits was within the limit set by WHO for all of the three studied hydroponic solutions.Dung dịch dinh dưỡng trong phương pháp thủy canh là yếu tố quyết định đến năng suất và chất lượng cây trồng. Trong nghiên cứu này, ảnh hưởng của 3 dung dịch dinh dưỡng phổ biến gồm Hoagland, TC Mobi và Knop đến sinh trưởng, năng suất và chất lượng quả của cây cà giống Chanoka F1 đã được đánh giá. Kết quả nghiên cứu cho thấy, dung dịch Hoagland có tác động tích cực hơn tới các chỉ tiêu sinh trưởng và chất lượng quả của cây cà chua Chanoka F1 so với hai dung dịch còn lại. Cây cà chua trồng trong dung dịch Knop có năng suất và chất lượng thấp nhất. Hàm lượng nitrat trong quả nằm trong giới hạn an toàn của WHO khi cây được trồng trong cả ba dung dịch nghiên cứu

Wood architecture and composition are deeply remodeled in frost sensitive eucalyptus overexpressing CBF/DREB1 transcription factors

Eucalypts are the most planted trees worldwide, but most of them are frost sensitive. Overexpressing transcription factors for CRT-repeat binding factors (CBFs) in transgenic Eucalyptus confer cold resistance both in leaves and stems. While wood plays crucial roles in trees and is affected by environmental cues, its potential role in adaptation to cold stress has been neglected. Here, we addressed this question by investigating the changes occurring in wood in response to the overexpression of two CBFs, taking advantage of available transgenic Eucalyptus lines. We performed histological, biochemical, and transcriptomic analyses on xylem samples. CBF ectopic expression led to a reduction of both primary and secondary growth, and triggered changes in xylem architecture with smaller and more frequent vessels and fibers exhibiting reduced lumens. In addition, lignin content and syringyl/guaiacyl (S/G) ratio increased. Consistently, many genes of the phenylpropanoid and lignin branch pathway were upregulated. Most of the features of xylem remodeling induced by CBF overexpression are reminiscent of those observed after long exposure of Eucalyptus trees to chilling temperatures. Altogether, these results suggest that CBF plays a central role in the cross-talk between response to cold and wood formation and that the remodeling of wood is part of the adaptive strategies to face cold stress.The Centre National pour la Recherche Scientifique (CNRS), the University Paul Sabatier Toulouse III (UPS), the French MERI (Ministry of Education, Research and Innovation), and the French Laboratory of Excellence project ‘TULIP’(ANR-10-LABX-41; ANR-11-IDEX-0002-02). This research was also financially supported by the Vietnamese government for PhD grants (P.B. Cao and C. Nguyen).http://www.mdpi.com/journal/ijmshj2020BiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant Patholog

Explosive Tandem and Segmental Duplications of Multigenic Families in Eucalyptus grandis

International audiencePlant organisms contain a large number of genes belonging to numerous multigenic families whose evolution size reflects some functional constraints. Sequences from eight multigenic families, involved in biotic and abiotic responses, have been analyzed in Eucalyptus grandis and compared with Arabidopsis thaliana. Two transcription factor families APETALA 2 (AP2)/ethylene responsive factor and GRAS, two auxin transporter families PIN-FORMED and AUX/LAX, two oxidoreductase families (ascorbate peroxidases [APx] and Class III peroxidases [CIII Prx]), and two families of protective molecules late embryogenesis abundant (LEA) and DNAj were annotated in expert and exhaustive manner. Many recent tandem duplications leading to the emergence of species-specific gene clusters and the explosion of the gene numbers have been observed for the AP2, GRAS, LEA, PIN, and CIII Prx in E. grandis, while the APx, the AUX/LAX and DNAj are conserved between species. Although no direct evidence has yet demonstrated the roles of these recent duplicated genes observed in E. grandis, this could indicate their putative implications in the morphological and physiological characteristicsofE. grandis, andbethekeyfactorforthesurvivalofthisnondormantspecies.Globalanalysisofkeyfamilieswouldbea good criterion to evaluate the capabilities of some organisms to adapt to environmental variations