Comparative d2/d3 LSU-rDNA sequence study of some Iranian Pratylenchus loosi populations.

The D-2/D-3 LSU rDNA expansion segment of 13 isolates attaching tea shrubs roots in tea gardens that verified by morphological and morphometrical studies as Pratylenchus loosi Loof, 1960 from Guilan province, North of Iran, were amplified and sequenced. Amplification of the D-2/D-3 LSU rDNA expansion segments yielded one fragment at over all sequenced isolates as 787 bp in size. The DNA sequences were aligned using Clustral X1.81 together and with three sequences of similar region of P. loosi isolates available in Genbank database (Isolate T from Serilanka and Isolates N1 and N2 from Florida, USA). Also the genetic distance between sequences data were calculated through four methods as following; Uncorrected distance (UC), Jukes-Cantor (JC) Kimura distance (K) and Jin-Neigamma distance (JNG). For generating phyllogenetic trees both Neighbor-joining (NJ) and Unweighted Pair Group Method with Arithmetic Mean (UPGMA) were used. The results indicated that very short genetic distance exist among the Iranian isolates and between the Iranian isolates and isolate T from Serilanka whereas the Iranian isolates and isolate T were genetically distinct from isolates N1 and N2. The phyllogenetic analyses revealed relationship not only among Iranian isolates but also between Iranian isolates and isolate T.