The fitness of Plutella xylostella L. on different genetically manipulated Brassica plants, including canola's progenitor (Brassica rapa L.), two cultivated canola cultivars (Opera and RGS003), one hybrid (Hyula401), one gamma-ray mutant-RGS003, and one transgenic (PF) genotype was compared using two-sex and female-based life table parameters. All experiments were conducted in a growth chamber at 25±1°C, 65±5% relative humidity, and a photoperiod of 16:8 (L:D) h. There were significant differences in duration of different life stages of P. xylostella on different plant genotypes. The shortest (13.92 d) and longest (24.61 d) total developmental time were on Opera and PF, respectively. The intrinsic rate of increase of P. xylostella ranged between 0.236 (Opera) and 0.071 day(-1) (PF). The highest (60.79 offspring) and lowest (7.88 offspring) net reproductive rates were observed on Opera and PF, respectively. Comparison of intrinsic rate of increase, net reproductive rates, finite rate of increase, mean generation time, fecundity, and survivorship of P. xylostella on the plant genotypes suggested that this pest performed well on cultivars (RGS003 and Opera) and performed poorly on the other manipulated genotypes especially on mutant-RGS003 and PF. Glucosinolate levels were significantly higher in damaged plants than undamaged ones and the lowest and highest concentrations of glucosinolates were found in transgenic genotype and canola's progenitor, respectively. Interestingly, our results showed that performance and fitness of this pest was better on canola's progenitor and cultivated plants, which had high levels of glucosinolate.
Phytoplasmas that are associated with fruit crops, vegetables, cereal and oilseed crops, trees, ornamental, and weeds are increasing at an alarming rate in the Middle East. Up to now, fourteen 16Sr groups of phytoplasma have been identified in association with more than 164 plant species in this region. Peanut witches’ broom phytoplasma strains (16SrII) are the prevalent group, especially in the south of Iran and Gulf states, and have been found to be associated with 81 host plant species. In addition, phytoplasmas belonging to the 16SrVI, 16SrIX, and 16SrXII groups have been frequently reported from a wide range of crops. On the other hand, phytoplasmas belonging to 16SrIV, 16SrV, 16SrX, 16SrXI, 16SrXIV, and 16SrXXIX groups have limited geographical distribution and host range. Twenty-two insect vectors have been reported as putative phytoplasma vectors in the Middle East, of which Orosius albicinctus can transmit diverse phytoplasma strains. Almond witches’ broom, tomato big bud, lime witches’ broom, and alfalfa witches’ broom are known as the most destructive diseases. The review summarizes phytoplasma diseases in the Middle East, with specific emphasis on the occurrence, host range, and transmission of the most common phytoplasma groups.
Zinnia elegans plants showing symptoms of phyllody, virescence, witches' broom, little leaf and yellowing were observed in Bandar Abbas, Hormozgan Province, Iran. Analysis showed that the phytoplasma shares a 99% sequence identity with BCandidatus Phytoplasma aurantifolia^and is a strain related to this species. To the authors' knowledge, this is the first report of the occurrence of a 16SrII phytoplasma infecting Zinnia elegans flowers.
Samples of Cota tinctoria with phytoplasma symptoms including witches' broom, stunting, twisting of the shoots and little leaf were observed in Bandar Abbas, Iran, in 2017. Phylogenetic analysis revealed that the phytoplasma associated with Cota tinctoria witches' broom (CtWB) is a strain of 'Candidatus Phytoplasma trifolii'. Furthermore, the phytoplasma was successfully detected in the leafhopper, Orosius albicinctus collected from the symptom-bearing plants. This work therefore reports a new phytoplasma-associated disease on Cota tinctoria and its putative insect vector.
A petunia witches’ broom (PvWB) disease, characterized by phyllody, virescence, witches’ broom, little leaf and yellowing, was observed in municipal lands and parks in Bandar Abbas, Hormozgan province, Iran. The disease was present with an average incidence of 20%. PCR and sequencing analysis carried out on selected samples from symptomatic plants showed the presence of a phytoplasma associated with the disease. The molecular comparison of the 16S ribosomal gene indicated 99% sequence identity with the one of “Candidatus Phytoplasma australasia”. This phytoplasma was transmitted to healthy petunia plants under experimental conditions by the leafhopper Orosius albicinctus that was then demonstrated to be a vector of this phytoplasma.
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