Effect of DL-β-amino-n-butyric acid on okra plants infected with different initial populations of Meloidogyne javanica

Habiballah Chadegani

DL-β-amino-n-butyric acid (BABA) induces resistance in plants against root-knot nematodes (Meloidogyne spp.) by activating natural defense mechanisms. This study evaluated the effect of BABA on the resistance of okra (Abelmoschus esculentus cv. Clemson Spineless) to M. javanica under greenhouse conditions. Seeds were sown in 1 kg plastic pots and maintained at 27 ± 3℃ under a 16:8 hours of light-dark cycle and with daily irrigation. At the four-leaf stage, seedlings were foliar-sprayed with BABA at concentrations of 0 (control), 0.5, 1, and 2 mM. After 24 hours, plants were inoculated with M. javanica at initial population densities of 0 (control), 1, 2, 4, and 8 second-stage juveniles (J2s). Sixty days post-inoculation, plant growth and nematode reproduction indices were assessed. Results showed that higher BABA concentrations significantly improved plants growth and reduced nematodes populations. Plants treated with 2 mM of BABA and inoculated with 8, 4, 2 and 1 J2s showed increases in shoot length by 43.9%, 45.1%, 32.5%, and 32.2%, respectively; shoot fresh weight by 37%, 38.2%, 69%, and 61.5%; and shoot dry weight by 23.5%, 24.5%, 37.4% and 39.7% compared to untreated control. Meanwhile, the nematode reproduction factor decreased by 25.1%, 25.9%, 14.1% and 38.4%, respectively. This study demonstrated that BABA application improves okra growth against M. javanica. Although BABA had no significant effect on the reproduction factor at the highest nematode population level, all concentrations improved plant growth, even under severe nematode pressure. Foliar application of 2 mM BABA effectively enhances okra resistance to M. javanica under greenhouse conditions.

Molecular detection of Potato virus S in Mazandaran Province, Iran

SeyyedehAtefeh Hosseini

Potato virus S (PVS) is one of the damaging and limiting agents affecting potato cultivation in Mazandaran Province, in north Iran. This virus belongs to the genus Carlavirus, characterized by an isometric particle morphology, a single-stranded RNA genome, and a relatively narrow host range. PVS typically exhibits an additive effect and is often found in co-infection with other potato viruses. Considering the observed symptoms of the spread and damage caused by this virus in potato fields of Mazandaran Province, this study was conducted to carry out molecular identification and determine the distribution areas of the virus within the province. A total of 94 plant samples were collected from potato fields in three regions; Savadkuh, Galugah, and Parkuh, in Mazandaran Province during 2023–2024. Total viral RNA was extracted from samples displaying severe disease symptoms, and the coat protein gene region of the virus was amplified using RT-PCR. A band of 1,118 base pairs was detected. One positive sample from each region was selected and sent to Macrogen Inc. (South Korea) for sequencing. After sequencing, the similarity of the obtained sequences to the corresponding gene region of other isolates of this virus was determined using phylogenetic software. The results showed that Iranian isolates of this virus fall into two groups; Group I: includes isolates from Iran, Syria, South Korea, China, and Germany, while Group II contains only two Iranian isolates. The molecular identification of isolates of this virus in this province, their distribution areas, and their genetic similarity to isolates from other countries are reported for the first time.

Plant Pathology Science

Effect of DL-β-amino-n-butyric acid on okra plants infected with different initial populations of Meloidogyne javanica

Molecular detection of Potato virus S in Mazandaran Province, Iran