Seasonal occurrence of spotted wing drosophila in various small fruits and berries in Pennsylvania and Maryland

Spotted wing drosophila (SWD) (Drosophila suzukii), a major invasive pest of small fruit crops, was first found in Pennsylvania and Maryland during the 2011 crop season, and since then, it has been established throughout the fruit growing regions of both states. A season‐long field study was conducted to find out the seasonal occurrence of SWD in several fruit crops (e.g. blueberry, tart and sweet cherry, floricane‐fruiting summer red raspberry, blackberry, primocane‐fruiting fall raspberries and table grapes) in Pennsylvania and Maryland in 2014. This is the first study determining seasonal occurrence of SWD using a standard commercial lure (Pherocon^® SWD Dual‐Lure^?)‐baited traps in this region. In both states, SWD adults were not captured prior to the month of July, and populations of SWD were found to build up in fruit crops only from mid‐July onwards. This indicates early season fruit crops or varieties are not at risk from SWD fruit injury in these two states. Such early fruit crops, for instance strawberry, sweet and tart cherry, are generally harvested before SWD populations build up in this region. In this context, implications of SWD population in various small fruit crops grown in this region and the utility of SWD Dual‐Lure ^? in season‐long monitoring of SWD population are discussed.     

Construction of an intra-specific sweet cherry (<Emphasis Type="Italic">Prunus avium</Emphasis> L.) genetic linkage map and synteny analysis with the <Emphasis Type="Italic">Prunus</Emphasis> reference map

Linkage maps of the sweet cherry cultivar ‘Emperor Francis’ (EF) and the wild forest cherry ‘New York 54’ (NY) were constructed using primarily simple sequence repeat (SSR) markers and gene-derived markers with known positions on the Prunus reference map. The success rate for identifying SSR markers that could be placed on either the EF or NY maps was only 26% due to two factors: a reduced transferability of other Prunus-species-derived markers and a low level of polymorphism in the mapping parents. To increase marker density, we developed four cleaved amplified polymorphic sequence markers (CAPS), 19 derived CAPS markers, and four insertion–deletion markers for cherry based on 101 Prunus expressed sequence tags. In addition, four gene-derived markers representing orthologs of a tomato vacuolar invertase and fruit size gene and two sour cherry sorbitol transporters were developed. To complete the linkage analysis, 61 amplified fragment length polymorphism and seven sequence-related amplified polymorphism markers were also used for map construction. This analysis resulted in the expected eight linkage groups for both parents. The EF and NY maps were 711.1 cM and 565.8 cM, respectively, with the average distance between markers of 4.94 cM and 6.22 cM. A total of 82 shared markers between the EF and NY maps and the Prunus reference map showed that the majority of the marker orders were the same with the Prunus reference map suggesting that the cherry genome is colinear with that of the other diploid Prunus species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">S</Emphasis> genotyping and <Emphasis Type="Italic">S</Emphasis> screening utilizing <Emphasis Type="Italic">SFB</Emphasis> gene polymorphism in Japanese plum and sweet cherry by dot-blot analysis

Most Rosaceae fruit trees such as Japanese plum and sweet cherry have a gametophytic self-incompatibility (GSI) system controlled by a single S locus containing at least two linked genes with multiple alleles, i.e., S-RNase as a pistil determinant and SFB (S-haplotype-specific F-box gene) as a candidate for the pollen S determinant. For identification of S genotypes, many methods based on polymerase chain reaction (PCR) utilizing polymorphism in length of the S-RNase and SFB gene have been developed. In this study, we developed two dot-blot analysis methods for S-haplotype identification utilizing allele-specific oligonucleotides based on the SFB-HVa region, which has high sequence polymorphism. Dot-blotting of allele-specific oligonucleotides hybridized with digoxigenin-labeled PCR products allowed S genotyping of plants with nine S haplotypes (S-a, S-b, S-c, S-e, S-f, S-h, S-k, S-7 and S-10) in Japanese plum and ten S haplotypes (S-1, S-2, S-3, S-4, S-4′, S-5, S-6, S-7, S-9 and S-16) in sweet cherry (dot-blot-S-genotyping). In addition, dot-blotting of PCR products of SFB probed with the allele-specific oligonucleotides, occasionally utilizing competitive hybridization, was successful in screening for a desirable S haplotype in sweet cherry (dot-blot-S-screening).     

Characterization of novel microsatellites and development of multiplex PCR for large‐scale population studies in wild cherry,Prunus avium

Primers were developed for 14 microsatellite or simple sequence repeat (SSR) loci identified from a Prunus avium‘Charger’ genomic DNA library. In a survey of 16 wild cherry accessions 10 of the loci revealed polymorphisms of between two and six alleles. The remaining loci were found to be monomorphic. Seven polymorphic loci identified in this study and four polymorphic loci previously reported in sweet cherry were mapped and found to be unlinked. Two multiplex polymerase chain reactions (PCR) were optimized to enable the characterization of all 11 unlinked, polymorphic SSR loci.     

Susceptibility of Thirty Cherry Genotypes on Phytophthora cactorum, P. citrophthora, P. citricola and P. parasitica

The diseases Phytophthor a crown and root rot consist of the most important problems in cherry cultivation. In this study, the susceptibility of 30 cherry genotypes to Phytophthora cactorum , P. citrophthora, P. parasitica and P. citricola was evaluated by using excised twig assay, excised shoot method and stem inoculation method. The results showed that all cherry genotypes tested were susceptible to all Phytophthora isolates used. Phytophthora parasitica and P. citrophthora were the most aggressive species. Host specificity of the Phytophthora isolates used in this study was not found although these isolates were from different plant species. In conclusion, because none of the cherry genotype showed a level of resistance to these pathogens, caution should be taken when these genotypes are used in locations, where these diseases are endemic.     

Unbiased estimation of greenhouse whitefly, Trialeurodes vaporariorum, mean density using yellow sticky trap in cherry tomato greenhouses

The spatial distribution of the count of adult greenhouse whiteflies, Trialeurodes vaporariorum (Westwood), on yellow sticky traps was analyzed using Taylor's power law and spatial autocorrelation statistics in the cherry tomato greenhouses from 1998–1999. Samples were collected weekly using a cylindrically shaped yellow sticky trap placed in a 5 by 8 grid covering 0.10–0.15 ha in each of five cherry tomato greenhouses. Taylor's (1961) power law indicated that counts of T. vaporariorum on traps were aggregated within greenhouses. Spatial autocorrelation analysis showed that trap catches were similar (positively autocorrelated) to a distance of 12.5 m, and then dissimilar (negatively autocorrelated) at >12.5 m. Autocorrelation-lag plots showed a globally significant spatial relation in 34 of 57 sample-weeks according to Bonferroni's approximation. The presence of this spatial relation was not related to the changes of mean density. Trap counts at the second lag distance (12.5–25 m) showed little spatial autocorrelation and tended to be the most spatially independent. A fixed-precision-level sequential sampling plan was developed using the parameters from Taylor's power law. The presence of spatial dependency in data sets degraded the sampling plan's precision relative to performance in data sets lacking significant spatial autocorrelation. Therefore, to obtain an unbiased mean density of T. vaporariorum per greenhouse, sticky traps should be placed at least >12.5 m apart to ensure that they are spatially independent.     

Roles of jasmonic acid in the development of sweet cherries as measured from fruit or disc samples

The effect of jasmonic acid (JA) on callus formation was investigated ondiscs taken from the pulp of sweet cherry fruit (Prunusavium L.). The discs were sampled at 16 days after full bloom(DAFB),22 DAFB, and 29 DAFB and cultured on B5 medium involving different combinationsof 1-naphthaleneacetic acid (NAA), N⁶-benzyl adenine (BA), and JA.Only at 16 DAFB, 1.0 M JA concentration increased callusweightgain relative to discs incubated without hormonal additives, although JAinhibited, or had no effect on callus formation, at 22 and 29 DAFB. The weightof the callus, which was subcultured, was also increased by 0.45–1.0M JA, without hormonal additives. Although the number of cellsincreased until 15 DAFB, after this time it did not change. These resultsdemonstrate that endogenous JA may be related to cell division in sweet cherryfruit. The interactions between JA and abscisic acid (ABA) were alsoinvestigated. Discs from pulp at 20 DAFB (immaturity), 32 DAFB (beforematuration), and 48 DAFB (maturation) were placed in petri dishes containing 10ml 0.4 M mannitol with JA or ABA. In addition, at 48DAFB, JA or ABA solutions had been absorbed by the fruit for 7 days via theshoot. ABA treatment did not influence endogenous JA concentrations in discs,with few exceptions. Although the ABA concentration in the fruit increased to2.2 times that of the control by ABA the 7 day treatment, endogenous JA failedto increase. Thus, ABA may not influence the JA pathway in sweet cherry fruit.Although the increase of endogenous ABA was observed in discs at earlier timesafter JA treatment, ABA concentration decreased in the fruit treated for 7 dayswith JA. This implies that the concentration of JA may influence ABA levels. JAtreatment did not influence anthocyanin accumulation, in spite of the increaseof JA in the fruit by the treatment. JA may not play a role in anthocyaninaccumulation in sweet cherry fruit.     

胸腺肽基因对樱桃番茄的遗传转化

胸腺肽基因是一343bp的小肽基因,是从动物中克隆得到的。本文以“美味樱桃”番茄为植物材料,用农杆菌侵染法进行了胸腺肽基因的遗传转化。对所得再生植株进行了PCR和Southern blot检测及RT-PCR检测,34棵Kam抗性株通过目的基因PCR检测,4棵为阳性株,阳性株率为11．8%。实验中还对目的基因之后的Nos终止序列区进行了扩增,通过Nos Ter．引物对4株目的基因PCR阳性株作PCR检测．只有1株为阳性株,该植株经Southern blot检测和RT-PCR检测,均为阳性。这些检测结果说明胸腺肽基因成功地整合到番茄基因组中,并在转录水平上得以表达。