Authors :

Arnaud Bellec, Audrey Courtial, Stephane Cauet, Nathalie Rodde, Sonia Vautrin, Genseric Beydon, Nadege Arnal, Nadine Gautier, Joelle Fourment, Elisa Prat, William Marande, Yves Barriere and Helene Berges.

Journal of Next Generation Sequencing & Applications.

Abstract :

Background:
Numerous completed or on-going whole genome sequencing projects have highlighted the fact that obtaining a high quality genome sequence is necessary to address comparative genomics questions such as structural variations among genotypes and gain or loss of specific function. Despite the spectacular progress that has been made in sequencing technologies, obtaining accurate and reliable data is still a challenge, both at the whole genome scale and when targeting specific genomic regions. These problems are even more noticeable for complex plant genomes. Most plant genomes are known to be particularly challenging due to their size, high density of repetitive elements and various levels of ploidy. To overcome these problems, we have developed a strategy to reduce genome complexity by using the large insert BAC libraries combined with next generation sequencing technologies.

Results:
We compared two different technologies (Roche-454 and Pacific Biosciences PacBio RS II) to sequence pools of BAC clones in order to obtain the best quality sequence. We targeted nine BAC clones from different species (maize, wheat, strawberry, barley, sugarcane and sunflower) known to be complex in terms of sequence assembly. We sequenced the pools of the nine BAC clones with both technologies. We compared assembly results and highlighted differences due to the sequencing technologies used.

Conclusions:
We demonstrated that the long reads obtained with the PacBio RS II technology serve to obtain a better and more reliable assembly, notably by preventing errors due to duplicated or repetitive sequences in the same region.

Link :

http://www.omicsonline.org/open-access/long-read-sequencing-technology-to-solve-complex-genomic-regionsassembly-in-plants-2469-9853-1000128.pdf

Authors :

Dobrovolskaya O, Pont C, Sibout R, Martinek P, Badaeva E, Murat F, Chosson A, Watanabe N, Prat E, Gautier N, Gautier V, Poncet C, Orlov Y, Krasnikov A, Bergès H, Salina E, Laikova L, Salse J.

Plant Physiol. 2015 Jan;167(1):189-99. doi: 10.1104/pp.114.250043

Abstract :

Bread wheat (Triticum aestivum) inflorescences, or spikes, are characteristically unbranched and normally bear one spikelet per rachis node. Wheat mutants on which supernumerary spikelets (SSs) develop are particularly useful resources for work towards understanding the genetic mechanisms underlying wheat inflorescence architecture and, ultimately, yield components. Here, we report the characterization of genetically unrelated mutants leading to the identification of the wheat FRIZZY PANICLE (FZP) gene, encoding a member of the APETALA2/Ethylene Response Factor transcription factor family, which drives the SS trait in bread wheat. Structural and functional characterization of the three wheat FZP homoeologous genes (WFZP) revealed that coding mutations of WFZP-D cause the SS phenotype, with the most severe effect when WFZP-D lesions are combined with a frameshift mutation in WFZP-A. We provide WFZP-based resources that may be useful for genetic manipulations with the aim of improving bread wheat yield by increasing grain number.

Link : http://www.ncbi.nlm.nih.gov/pubmed/25398545