باکتری‌های همراه با گره ریشه توسکا ییلاقی در ایران

Alnus subcordata, also known as the Caucasian alder, is a highly beneficial species for afforestation due to its rapid growth, nitrogen-fixing ability, and positive impact on soil fertility. This tree may change the soil microbial community and play a vital role in nutrient cycling. In Iran, Caucasian alder is one of the most valuable commercial species in the northern forests. In the summer of 2020, nodulated Caucasian alder roots were collected from the Hyrcanian (Caspian) forests in northern Iran (Chalus county, western Mazandaran) and brought, in paper bags, to the laboratory. The roots and their associated nodules were thoroughly washed with tap water to remove the mud and soil particles. The nodules were separated from the roots, surface disinfected with 1% (v/v) sodium hypochlorite for two min and washed several times using sterile distilled water (SDW). They were then placed in drops of SDW in a Petri dish and crushed finely using a sterile scalpel. Loopfuls of the resulting suspension, 20-30 min following crushing, were streaked onto plates of Yeast mannitol agar (YMA) and sucrose nutrient agar (SNA, 1% sucrose). Three to five days after incubation at 25-28°C, bacterial colonies appeared on plates. After purification of bacterial colonies, 10 isolates were selected and subjected to molecular tests. DNA was extracted from the isolates and a part of the 16S rRNA gene (approximately 1200 bp) was amplified and sequenced. Comparison of the nucleotide sequence with those present in GenBank indicated 98-99% identity of the isolates (GenBank accession numbers: OR648117, OR648116, OR648114, PP901864, PP901865, PP916592, OR648092, PP892070, OR648175, OR648115) with those of Bradyrhizobium, Rhizobium, Bacillus and Achromobacter, respectively. This is the first report on isolation of Bradyrhizobium, Bacillus, and Achromobacter from Alnus subcordata root nodules in Iran.