Abstract

RIVERA PAEZ, Fredy Arvey; GONZALEZ SALAZAR, Viviana; GONZALEZ ACOSTA, Jorge Giovany  and  OSSA LOPEZ, Paula Andrea. Molecular characterization, morphological analysis and mycorrhizal colonization in the avocado (Persea americana Mill) rhizosphere in Caldas, Colombia. Acta Agron. [online]. 2016, vol.65, n.4, pp.398-405. ISSN 0120-2812.  https://doi.org/10.15446/acag.v65n4.51714.

Families of arbuscular mycorrhizal fungi (AMF) associated to two varieties of avocado Persea americana Mill (hass and lorena), in 12 samples of rhizosphere soil and roots in Caldas, Colombia were evaluated. Spores were obtained by wet sieving and sucrose gradient centrifugation, and mounted on polyvinyl alcohol using glycerol and Melzer's reagents, to determine their morphology, and roots treated con potassium hydroxide, acetic acid, Trypan Blue and lactoglycerol, to establish colonization. The DNA was extracted by DNeasy Plant Mini Kit (Qiagen™) and amplified by PCR using primers for genes 18S and 28S nuclear rDNA, visualized and purified on agarose gels and sequenced by Macrogen Advancing throughout Genomics-South Korea. The results show presence of 12 morphotypes belonging to the families Acaulosporaceae, Gigasporaceae, Diversisporaceae and Glomeraceae, and mycorrhizal colonization higher 90% in both varieties of avocado. It was possible to isolate DNA of nine morphotypes and amplify seven. Alignment of DNA sequences carried out in the ClustaW software included in the program Mega 6, together with sequences deposited in GenBank, using the distance parameter Kimura 2 (K2P), they allowed to build a tree of similarity for the method Neighbor-Joining (NJ) clustering the samples determined by morphology in the corresponding taxonomical families. These results allowed to standardize protocols for families in this group, where his taxonomy is difficult and controversial, registering families cited in the literature as highly important for the protection and incorporation of nutrients into the plant.

Keywords : AMF morphotypes; DNA sequence alignment; ribosomal genes; symbiosis, taxonomy.

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