Genome-wide transcriptome analysis reveals small RNA profiles involved in early stages of stolon-to-tuber transitions in potato under photoperiodic conditions

Abstract Background Small RNAs (sRNAs), especially miRNAs, act as crucial regulators of plant growth and development. Two other sRNA groups, trans-acting short-interfering RNAs (tasiRNAs) or phased siRNAs (phasiRNAs), are also emerging as potential regulators of plant development. Stolon-to-tuber transition in potato is an important developmental phase governed by many environmental, biochemical and hormonal cues. Among different environmental factors, photoperiod has a major influence on tuberization. Several mobile signals, mRNAs, proteins and transcription factors have been widely studied for their role in tuber formation in potato, however, no information is yet available that describes the molecular signals governing the early stages of stolon transitions or cell-fate changes at the stolon tip before it matures to potato. Stolon could be an interesting model for studying below ground organ development and we hypothesize that small RNAs might be involved in regulation of stolon-to-tuber transition process in potato. Also, there is no literature that describes the phased siRNAs in potato development. Results We performed sRNA profiling of early stolon stages (4, 7 and 10 d) under long-day (LD; 16 h light, 8 h dark) and short-day (SD; 8 h light, 16 h dark) photoperiodic conditions. Altogether, 7 (out of 324) conserved and 12 (out of 311) novel miRNAs showed differential expression in early stolon stages under SD vs LD photoperiodic conditions. Key target genes (StGRAS, StTCP2/4 and StPTB6) exhibited differential expression in early stolon stages under SD vs LD photoperiodic conditions, indicative of their potential role in tuberization. Out of 830 TAS-like loci identified, 24 were cleaved by miRNAs to generate 190 phased siRNAs. Some of them targeted crucial tuberization genes such as StPTB1, POTH1 and StCDPKs. Two conserved TAS loci, referred as StTAS3 and StTAS5, which share close conservation with members of the Solanaceae family, were identified in our analysis. One TAS-like locus (StTm2) was validated for phased siRNA generation and one of its siRNA was predicted to cleave an important tuber marker gene StGA2ox1. Conclusion Our study suggests that sRNAs and their selective target genes could be associated with the regulation of early stages of stolon-to-tuber transitions in a photoperiod-dependent manner in potato

Development of a Virus‐Induced Gene Silencing System for Dioecious Coccinia grandis

International audienceCoccinia grandisis an interesting model system to understand dioecy in Cucurbitaceae family. Recent transcriptomics and proteomics studies carried out to understand the sex expression inC. grandishave resulted in identification of many candidate sex-biased genes. In absence of an efficient genetic transformation protocol forC. grandis, virus-induced gene silencing (VIGS) would be a powerful tool to enable gene functional analysis. In current study, we explored the apple latent spherical virus (ALSV) for gene knockdown inC. grandis.The viral infection was achieved through mechanical inoculation of ALSV-infectedChenopodium quinoaleaf extract onto the cotyledons ofC. grandis. ALSV-VIGS mediated knockdown ofCgPDSgene was successfully achieved inC. grandisby mechanical inoculation method resulting in characteristic photobleaching. Subsequently, we developed agroinfiltration compatible vectors for direct infection ofC. grandisand shortened the time-frame by skipping viral propagation inC. quinoa. Typical yellow-leaf phenotype was observed inC. grandisplants agroinfiltrated with ALSV-CgSUconstructs, indicating robust silencing ofCgSUgene. In addition, we improved the infection efficiency of ALSV by co-infiltration of P19 viral silencing suppressor. These results suggest that ALSV-VIGS is suitable for characterization of gene function in dioeciousC. grandisand it can help us understand the mechanism of sex expression

Alte Erinnerungen an das Elsass

Numérisé par le partenaireAppartient à l’ensemble documentaire : BNUStr001Appartient à l’ensemble documentaire : BNUStras1Numérisé par le partenair

The Seed Development Factors TT2 and MYB5 Regulate Heat Stress Response in Arabidopsis

International audienceHEAT SHOCK FACTOR A2 (HSFA2) is a regulator of multiple environmental stress responses required for stress acclimation. We analyzed HSFA2 co-regulated genes and identified 43 genes strongly co-regulated with HSFA2 during multiple stresses. Motif enrichment analysis revealed an over-representation of the site II element (SIIE) in the promoters of these genes. In a yeast 1-hybrid screen with the SIIE, we identified the closely related R2R3-MYB transcription factors TT2 and MYB5. We found overexpression of MYB5 or TT2 rendered plants heat stress tolerant. In contrast, tt2, myb5, and tt2/myb5 loss of function mutants showed heat stress hypersensitivity. Transient expression assays confirmed that MYB5 and TT2 can regulate the HSFA2 promoter together with the other members of the MBW complex, TT8 and TRANSPARENT TESTA GLABRA 1 (TTG1) and that the SIIE was involved in this regulation. Transcriptomic analysis revealed that TT2/MYB5 target promoters were enriched in SIIE. Overall, we report a new function of TT2 and MYB5 in stress resistance and a role in SIIE-mediated HSFA2 regulation

L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

27 septembre 19431943/09/27 (A44,N15536)