A BAC/BIBAC-based physical map of chickpea, Cicer arietinum L.
BACKGROUND
Chickpea (Cicer arietinum L.) is the third most important pulse crop worldwide. Despite its importance, relatively little is known about its genome. The availability of a genome-wide physical map allows rapid fine mapping of QTL, development of high-density genome maps, and sequencing of the entire genome. However, no such a physical map has been developed in chickpea.


RESULTS
We present a genome-wide, BAC/BIBAC-based physical map of chickpea developed by fingerprint analysis. Four chickpea BAC and BIBAC libraries, two of which were constructed in this study, were used. A total of 67,584 clones were fingerprinted, and 64,211 (~11.7 x) of the fingerprints validated and used in the physical map assembly. The physical map consists of 1,945 BAC/BIBAC contigs, with each containing an average of 28.3 clones and having an average physical length of 559 kb. The contigs collectively span approximately 1,088 Mb. By using the physical map, we identified the BAC/BIBAC contigs containing or closely linked to QTL4.1 for resistance to Didymella rabiei (RDR) and QTL8 for days to first flower (DTF), thus further verifying the physical map and confirming its utility in fine mapping and cloning of QTL.


CONCLUSIONS
The physical map represents the first genome-wide, BAC/BIBAC-based physical map of chickpea. This map, along with other genomic resources previously developed in the species and the genome sequences of related species (soybean, Medicago and Lotus), will provide a foundation necessary for many areas of advanced genomics research in chickpea and other legume species. The inclusion of transformation-ready BIBACs in the map greatly facilitates its utility in functional analysis of the legume genomes.
Zhang
Xiaojun
X
Department of Soil and Crop Sciences, Texas A&M University, College Station, Texas 77843-2474, USA.
Scheuring
Chantel F
CF
Zhang
Meiping
M
Dong
Jennifer J
JJ
Zhang
Yang
Y
Huang
James J
JJ
Lee
Mi-Kyung
MK
Abbo
Shahal
S
Sherman
Amir
A
Shtienberg
Dani
D
Chen
Weidong
W
Muehlbauer
Fred
F
Zhang
Hong-Bin
HB
D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics*; D029863:Cicer / Q000235:genetics*; D020451:Contig Mapping; D016172:DNA Fingerprinting; D015723:Gene Library; D018745:Genome, Plant / Q000235:genetics; D018598:Minisatellite Repeats / Q000235:genetics; D020161:Physical Chromosome Mapping / Q000379:methods*; D040641:Quantitative Trait Loci / Q000235:genetics