Phylogenetic Analysis of Some Indigenous and Non-Indigenous Luffa (Luffa cylindrica) Genotypes using ITS Marker

Luffa is a plant from the Cucurbitaceae family with the scientific name of Luffa cylindrica. In addition to the food consumption of mature green fruit and the medicinal and health properties of seed oil, it is important due to the fibrous spongy texture of its dried fruits. There is a great variety in terms of shape, size, quality of sponge, etc. among different cultivars of Luffa, the study of which helps plant breeders to identify the genetic capacity of traits associated with its important breeding goals.

In this study, the genetic diversity of 5 indigenous Lufa genotypes related to Mazandaran, Kerman, Sistan and Baluchestan provinces, and 3 non-Indigenous genotypes related to China, Brazil and Afghanistan were studied by evaluating the ITS (Internal transcribed spacer) ribosome region. After sampling of young leaves, DNA was extracted by Dellaporta method, and PCR was performed using a pair of ITS primers. After sequencing and qualification, amplified products were aligned and dendrogram of phylogenic relationships and difference and similarity matrix of sequences were determined.

In this research, from a total of 703 sites, 175 sites had deletion and addition (170 monomorphes and 5 polymorphs) and 528 sites were lake of deletion and addition. Most of the substitutes for the ITS sequence were transversion (55.5%), and only 44.5% of the substitutes were transitional type. Also, the mean ratio of thymine, cytosine, adenine and guanine was 9.18, 8.28, 19.9 and 42.4% of the total nucleotides. The average numerical value of DN / DS ratio was 0.86. The overall average of the genetic distance between the samples examined, for the ITS marker, using the Maximum Composite model was 0.107.

Studying the relationships between tested genotypes based on the ITS region, as analyzed in this study, showed the presence of intra-species variation in the genotypes of Luffa aegyptiaca studied. However, relatively low genetic distances between genotypes may indicate the relative weakness of this marker in the genetic studies of Luffa. Therefore, for a more accurate conclusion it is suggested that this marker is be used as a supplementary barcode with other markers.