Genetic characterization of differences between two distinct voltine populations of the European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera:Crambidae)

The inheritances of three life history traits contributing to voltinism were investigated in two latitudinally distinct ecotypes of the European corn borer, Ostrinia nubilalis (Hübner). While critical photoperiod and post-diapause development time (PDD) were clearly different, larval development time did not play a critical role in differences between the expression of voltinism in the ecotypes tested. The ecotype adapted to a bivoltine habitat exhibited shorter critical photoperiod (14.80 hour) than the ecotype (15.33 hour) that originating from a univoltine habitat. The F1 progenies had somewhat intermediate responses with clear indication of a sex-linked inheritance. The F2 progenies further affirmed that the male parent had more influence on the offspring\u27s diapause response than the female parent. The minimum number of genes estimates and the response from backcross progenies suggested that the critical photoperiod is controlled by a few loci, one of which may be located on the sex chromosome. Correspondingly, the PDD in both ecotypes demonstrated the adaptive importance of this trait for voltinism, with the southern population completing PDD earlier than the northern ecotype. The F1 crosses had responses consistent with an apparent sex linkage. The further crosses indicated that the male parent had more influence on the PDD times of the resulting progenies. The overall results indicated that both ecotypes had adopted unique diapause responses, which ultimately leads to seasonal synchrony in their ecosytem. Furthermore, the presence of genetic variation within each ecotype was discussed

Construction of genetic linkage map for Ficus carica L. based on AFLP, SSR, and SRAP markers

A new genetic linkage map of Ficus carica (2n=2x=26) was constructed using 149 F1 progeny derived from the cross between two fig cultivars, 'Bursa Siyah' (BS) and 'Ak Ilek' (AK). Fifty-two amplified fragment length polymorphism, 49 simple sequence repeat (SSR), 16 sequence-related amplified polymorphism (SRAP), and 12 sequence characterized amplified region (SCAR-SRAP) combinations were used to generate markers for the map. The BS map consisted of 229 markers, distributed to 16 linkage groups (LGs), with an average marker density of 5.98 cM and map distance of 1342 cM. The AK linkage map carried 244 markers, distributed to 16 LGs, with an average marker density of 4.90 cM and map distance of 1191 cM. The consensus map comprises 355 markers, 1474 cM in length, with average marker density of 4.15 cM. The map indicates the location of new SSRs, nine of which were transferred from related species, and might be helpful for mapping quantitative trait loci that control important horticultural traits in the future

Introgression of Resistance to Leafminer (Liriomyza cicerina Rondani) from Cicer reticulatum Ladiz. to C. arietinum L. and Relationships between Potential Biochemical Selection Criteria

The chickpea leafminer, Liriomyza cicerina (Rondani), is one of the most destructive insect pests of cultivated chickpea (Cicer arietinum L.) in the Mediterranean region under field conditions. For sustainable and environmentally friendly chickpea production, efforts have been devoted to managing the leafminer via decreasing the use of insecticides. Breeding of new resistant varieties is not only an efficient and practical approach, but also cost-effective and environmentally sensitive. To improve resistant varieties, breeders need reliable biochemical selection criteria that can be used in breeding programs. The first objective was to investigate the possible introgression of resistance to the leafminer from C. reticulatum Ladiz. (resistant) to C. arietinum (susceptible), then, to estimate inheritance of resistance to the leafminer for efficient breeding strategies, and finally, to study organic acid contents as selection criteria. Recombinant inbred lines (RILs) and their parents were evaluated using a visual scale of 1–9 (1 = free from leafminer damage and 9 = mines in more than 91% of the leaflets and defoliation greater than 31%) in the field under natural infestation conditions after the susceptible parent and check had scores of >7 on the visual scale. Superior RILs were found for resistance to the leafminer, and agro-morphological traits indicating that introgression of resistance to leaf miner from C. reticulatum to C. arietinum could be possible using interspecific crosses. The inheritance pattern of resistance to the leafminer in RILs was shown to be quantitative. Organic acids, including oxalic, malic, quinic, tartaric, citric and succinic acids in RILs grown in the field under insect epidemic conditions and in the greenhouse under non-infested conditions were detected by using high performance liquid chromatography (HPLC). In general, organic acids were found to be higher in resistant RILs than susceptible RILs. Path and correlation coefficients showed that succinic acid exhibited the highest direct effects on resistance to the leafminer. Multivariate analyses, including path, correlation and factor analyses suggested that a high level of succinic acid could be used as a potential biochemical selection criterion for resistance to leafminer in chickpea. Resistant RILs with a high seed yield resembling kabuli chickpea can be grown directly in the target environments under leaf miner infestation conditions

Developing, linkage mapping and phylogenetic analyses of AP2-EREBP type transcription factor markers in citrus

Ethylene responsive AP2/EREBP type transcription factors (TF) play major roles such as growth, development, and tolerance to biotic and abiotic stresses in plants. Forward and reverse AP2/EREBP type TF-specific primers were designed, sequenced, and linkage mapped in a population of 164 F-1 individuals derived between 'Clementine' mandarin (Citrus reticulata Blanco 'Clementine') and 'Orlando' tangelo' (C. paradisi Macf. 'Duncan' x C. reticulata Blanco 'Dancy'). A total of 26 pairs of primers were designed for PCR reactions using Primique software available in TF database (DATFAP) based on default parameters using available dicot's AP2/EREBP sequences. These primers included 17 to 35 bases, and produced a total of 21 polymorphic markers. Bright 13 markers were excised, sequenced, deposited in the NCBI web site, and BLAST-analyzed for homology. Of the 21 markers, 13 were linkage mapped in a previous citrus map. Seven and five markers were mapped in 'Clementine' and 'Orlando' map, respectively. Based on Maximum Parsimony algorithm nested in MEGA 4 evolutionary genetic analysis software, the 13 TF sequences obtained in this study were found to be closely related to known TFs of Arabidopsis thaliana. Few of TF markers were found to be closely linked in existing linkage map of citrus, suggesting possible ancestral origin. These AP2/EREBP primers helped identification of citrus AP2/EREBP type transcription factor genes and can be used in other dicots such as tomato and cotton may have potential in understanding evolutionary relationships, establishing linkage map, and estimating diversity among other dicots since these TFs may reflect adaptability of plants

Multiplex Real-Time qPCR Assay for Simultaneous and Sensitive Detection of Phytoplasmas in Sesame Plants and Insect Vectors

<div><p>Phyllody, a destructive and economically important disease worldwide caused by phytoplasma infections, is characterized by the abnormal development of floral structures into stunted leafy parts and contributes to serious losses in crop plants, including sesame (<i>Sesamum indicum</i> L.). Accurate identification, differentiation, and quantification of phyllody-causing phytoplasmas are essential for effective management of this plant disease and for selection of resistant sesame varieties. In this study, a diagnostic multiplex qPCR assay was developed using TaqMan^® chemistry based on detection of the 16S ribosomal RNA gene of phytoplasmas and the 18S ribosomal gene of sesame. Phytoplasma and sesame specific primers and probes labeled with different fluorescent dyes were used for simultaneous amplification of 16SrII and 16SrIX phytoplasmas in a single tube. The multiplex real-time qPCR assay allowed accurate detection, differentiation, and quantification of 16SrII and 16SrIX groups in 109 sesame plant and 92 insect vector samples tested. The assay was found to have a detection sensitivity of 1.8 x 10² and 1.6 x 10² DNA copies for absolute quantification of 16SrII and 16SrIX group phytoplasmas, respectively. Relative quantification was effective and reliable for determination of phyllody phytoplasma DNA amounts normalized to sesame DNA in infected plant tissues. The development of this qPCR assay provides a method for the rapid measurement of infection loads to identify resistance levels of sesame genotypes against phyllody phytoplasma disease.</p></div

Inheritance and Expressivity of Neoplasm Trait in Crosses between the Domestic Pea (Pisum sativum subsp. sativum) and Tall Wild Pea (Pisum sativum subsp. elatius)

The Neoplasm trait in pea pods is reported to be due to the lack of ultraviolet (UV) light in glasshouse conditions or in response to pea weevil (Bruchus pisorum L.) damage. This pod deformation arises from the growth of non-meristematic tissue on pods of domesticated peas (Pisum sativum L. subsp. sativum). Neither expressivity, nor the effect of pea weevil on neoplasm in the tall wild pea (P. sativum L. subsp. elatius (M. Bieb.) Asch. & Graebn.), have been adequately studied. We aimed to study the expression and inheritance of neoplasm in the tall wild pea and crosses between domesticated and tall wild peas grown in the glasshouse (without pea weevils) and in the field (with pea weevils) under natural infestation conditions. Neoplasm was found in all pods in tall wild peas when grown in the glasshouse, while it was not detected on pods of field-grown plants despite heavy pea weevil damage. In inter-subspecific crosses between P. sativum subsp. sativum and P. sativum subsp. elatius, all F-1 plants had neoplastic pods, and the F-2 populations segregated in a good fit ratio of 3 (neoplasm): 1 (free from neoplasm) under glasshouse conditions, which suggests that neoplasm on pods of the tall wild pea was controlled by a single dominant gene. Expressivity of neoplasm in the progeny differed from parent to parent used in inter-subspecific crosses. There was no relationship between neoplasm and damage by pea weevil under heavy insect epidemics under field conditions. The neoplasm occurring under glasshouse conditions may be due to one or to a combination of environmental factors. Since wild peas are useful genetic resources for breeding programs aiming at fresh pea production that could be utilized under glasshouse conditions, negative selection could be considered in segregating populations

Sequence alignment of the 16S ribosomal gene region used for amplification and specific detection of sesame 16Sr group II and IX phytoplasmas.

<p>Sequences of the primers and probes designed in this study are shown in underlined and italic letters, respectively. Forward primer SPHY-16SrII-IX-F (upper arrow, red), probe 16SrII (dotted line, blue) and 16SrIX (solid line, green), and reverse primer SPHY-16SrII-IX-R (lower arrow, red) are noted. The sequence differences between 16SrII and 16SrIX in the probe regions were shown in boxed letters.</p

Slope, intercept, correlation coefficients (R²), and efficiencies (E) of qPCR assay.

<p>Slope, intercept, correlation coefficients (R²), and efficiencies (E) of qPCR assay.</p

Standard curves generated from the multiplex qPCR amplification of seven 10-fold dilution series of 16SrII (A) and 16SrIX (B) group standards used to convert Ct values to the phytoplasma DNA copies present in the samples.

<p>The amplification mixture contained phytoplasma and sesame primers, as well as 16SrII, 16SrIX, and sesame probes. Each dilution series was added to 10 ng of uninfected sesame DNA per reaction as part of the inhibition experiments. Log₁₀ values of the initial copies of phytoplasma DNA are plotted against corresponding Ct values.</p