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First Report of Pestalotiopsis virgatula Causing Pestalotiopsis Fruit Rot on Rambutan in Hawaii

Keith LM

Plant Dis, 2008 May;92(5):835.
PMID: 30769617 DOI: 10.1094/PDIS-92-5-0835B

Rambutan (Nephelium lappaceum Linn.) is a tropical, exotic fruit that has a rapidly expanding niche market in Hawaii. Diseased rambutan fruit was commonly observed in orchards in the Hilo and Kona districts of Hawaii Island during 2006. In surveys conducted in January, symptoms appeared as dark brown-to-black spots on mature fruit and blackened areas at the base of spinterns (hair-like projections) of mature and immature fruits. Pieces of infected fruit (cv. R167) were surface sterilized for 2 min in 0.5% NaOCl, plated on potato dextrose agar, and incubated at 24 ± 1°C for 7 days. The fungus growing on PDA was pale buff with sparse, aerial mycelium and acervuli containing black, slimy spore masses. All isolates had five-celled conidia. Apical and basal cells were hyaline, while the three median cells were olivaceous; the upper two were slightly darker than the lower one. Conidia (n = 40) were 20.3 ± 0.1 × 6.8 ± 0.1 μm. There were typically three apical appendages averaging 16.8 ± 0.2 μm long. The average basal appendage was 3.8 ± 0.1 μm long. The fungus was initially identified as Pestalotiopsis virgatula (Kleb.) Stey. on the basis of conidial and cultural characteristics (3). The identification was confirmed by molecular analysis of the 5.8S subunit and flanking internal transcribed spacers (ITS1 and ITS2) of rDNA amplified from DNA extracted from single-spore cultures with the ITS1/ITS4 primers (1,4) and sequenced (GenBank Accession No. EU047943). To confirm pathogenicity, agar pieces, 3 mm in diameter, from 7-day old cultures were used as inoculum. Five mature fruit from rambutan cv. R134 were rinsed with tap water, surface sterilized with 0.5% NaOCl for 2 min, wounded with a needle head, inoculated in the laboratory, and maintained in a moist chamber for 7 days. Lesions resembling symptoms that occurred in the field were observed on fruit after 7 days. No symptoms were observed on fruit inoculated with agar media. The fungus reisolated from diseased fruit was identical to the original isolates, confirming Koch's postulates. The disease appears to be widespread in Hawaii. Preharvest symptoms may have the potential to affect postharvest fruit quality if fruits are not stored at the proper conditions. Pestalotiopsis spp. have been reported on rambutan in Malaysia, Brunei, and Australia (2). To my knowledge, this is the first report of P. virgatula causing fruit spots on rambutan in Hawaii. References: (1) G. Caetano-Annolles et al. Curr. Genet. 39:346, 2001. (2) D. F. Farr et al. Fungal Databases. Systematic Botany and Mycology Laboratory. On-line publication. ARS, USDA, 2007. (3) E. F. Guba. Monograph of Pestalotia and Monochaetia. Harvard University Press, Cambridge, MA, 1961. (4) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA. 1990.
First Report of Pestalotiopsis Leaf Blotch on Mangosteen in Hawaii

Keith LM, Matsumoto TK

Plant Dis, 2013 Jan;97(1):146.
PMID: 30722309 DOI: 10.1094/PDIS-07-12-0702-PDN

Mangosteen (Garcinia mangostana L.) is a tropical evergreen tree that produces one of the most prized tropical fruits, commonly known as the "Queen of the Fruits.″ Mangosteen has the potential to occupy a rapidly expanding niche market in Hawaii. In October 2009, a disease was observed that produced brown leaf spots and blotches surrounded by bright yellow halos at a mangosteen orchard located in Hakalau, Hawaii (19° 53' 49″ N, 155° 7' 35″ W). Recently transplanted 10+ year old trees were 95 to 100% infected. Pieces of infected leaves and stems were surface-sterilized, plated on potato dextrose agar (PDA), and incubated at 24°C ± 1°C for 21 days. The fungus growing on PDA was pale buff with sparse aerial mycelium and acervuli containing black, slimy spore masses. Single spore isolates were used for the morphological characteristics and molecular analysis. Conidia were 5-celled. Apical and basal cells were hyaline; the three median cells were umber to olivaceous. Conidia (n = 50) were 24.3 ± 0.2 × 7.5 ± 0.1 μm, with apical appendages, typically three, averaging 24.3 ± 0.4 μm long, and a basal appendage averaging 6.7 ± 0.2 μm long. DNA sequences were obtained from the β-tubulin gene and the internal transcribed spacer (ITS1 and ITS2) and 5.8S regions of the rDNA to confirm the identification. The morphological descriptions and measurements were similar to P. virgatula (Kleb.) Steyaert (1). Although sequence data of the ITS region (GenBank Accession No. JN542546) supports the identity of the fungus as P. virgatula, the taxonomy of this genus remains confused since there are only a few type cultures, so it is impossible to use sequences in GenBank to reliably clarify species names (2). To confirm pathogenicity, six leaves of two 3-year-old seedlings were inoculated. Seven-day-old cultures grown on 10% V8 agar at 24°C under continuous fluorescent lighting were used for inoculations. The inoculum consisted of spore suspensions in sterile distilled water adjusted to 6 × 105 conidia/ml. Using a fine haired paint brush, the inoculum was brushed onto the youngest leaves, while sterile distilled water was used as the control. The plants were incubated in a clear plastic bag placed on the laboratory bench at 24°C for 48 hours, then placed on a greenhouse bench and observed weekly for symptoms. After 14 days, leaf spots ranging in size from pinpoint to 5.4 mm in diameter with a distinctive yellow halo were present. Within 35 days, the leaf spots enlarged to leaf blotches ranging in size from 11.5 × 13.3 mm up to 28.3 × 34.6 mm with brown centers and a distinctive yellow halo identical to the field symptoms. A Pestalotiopsis sp. identical to that used to inoculate the seedlings was recovered from the leaf spots and blotches, confirming Koch's postulates. The experiment was repeated twice. Pestalotiopsis leaf blight has been reported in other countries growing mangosteen, including Thailand, Malaysia, and North Queensland, Australia (3). However, to our knowledge, this is the first report of a Pestalotiopsis sp. causing a disease on mangosteen in Hawaii. Although this disease is considered a minor problem in the literature (3), effective management practices should be established to avoid potential production losses. References: (1) E. F. Guba. Monograph of Pestalotia and Monochaetia. Harvard University Press, Cambridge, MA. 1961. (2) S. S. N. Maharachchikumbura et al. Fungal Div. 50:167, 2011. (3) R. C. Ploetz. Diseases of Tropical Fruit Crops. CABI Publishing. Wallingford, Oxfordshire, UK, 2003.
First Report of Dolabra nepheliae on Rambutan and Litchi in Hawaii and Puerto Rico

Rossman AY, Goenaga R, Keith L

Plant Dis, 2007 Dec;91(12):1685.
PMID: 30780638 DOI: 10.1094/PDIS-91-12-1685C

A stem canker disease on rambutan (Nephelium lappaceum L.) and litchi (Litchi chinensis Sonn. (Sapindaceae) was found in plants in Hawaii and Puerto Rico. A fungus associated with cankers was identified as Dolabra nepheliae C. Booth & Ting (1). Numerous black, stipitate, elongate ascomata were produced within cracks of cankers. These ascomata contain elongate, bitunicate asci amid unbranched, interthecial elements and thin, cylindrical, hyaline ascospores measuring 96 to 136 × 2.5 to 3.5 μm. This fungus was originally described from Malaysia on N. lappaceum (1) and is also known on pulasan (N. mutabile Blume) in Australia (2). Classified by the Food and Agriculture Organization as a 'minor disease', the canker appears to be relatively common in Hawaii and was most likely introduced into Puerto Rico on imported germplasm. Nevertheless, efforts are underway to study the potential damage of this disease as well as mechanisms of control, including introduction of disease resistant clones. Specimens have been deposited at the U.S. National Fungus Collections (Hawaii on Nephelium BPI 878189, Puerto Rico (PR) on Nephelium BPI 878188, and PR on Litchi BPI 878190). Although a specimen of D. nepheliae on L. chinensis was collected from Hawaii in 1984 by G. Wong and C. Hodges and deposited as BPI 626373, this fungus was not known on Nephelium spp. in Hawaii and was not previously known from Puerto Rico on either host. References: (1) C. Booth and W. P. Ting. Trans. Brit. Mycol. Soc. 47:235, 1964. (2) T. K. Lim and Y. Diczbalis. Rambutan. Page 306 in: The New Rural Industries. Online publication. Rural Industries Research and Development Corporation, Australia, 1997.
First Report of Dolabra nepheliae Associated with Corky Bark Disease of Langsat in Hawaii

Keith LM, Matsumoto TK, McQuate GT

Plant Dis, 2013 Jul;97(7):990.
PMID: 30722533 DOI: 10.1094/PDIS-09-12-0886-PDN

In January 2011, branch samples were collected from langsat (Lansium domesticum Corr.), a fruit from Southeast Asia with an expanding niche market in Hawaii, exhibiting corky bark symptoms similar to that found on rambutan (Nephelium lappaceum) and litchi (Litchi chinensis) (3). The orchard, located along the Hamakua Coast of Hawaii Island, had 5- to 10-year-old trees, all with corky bark symptoms. As the trees matured, the cankers increased in size and covered the branches and racemes, often resulting in little to no fruit production. Scattered along the infected bark tissue were elongated, black ascomata present in the cracks. Ascomata were removed from the cracks using a scalpel blade, placed at the edge of a water agar petri dish and gently rolled along the agar surface to remove bark tissue and other debris. Individual ascomata were placed in 10-μl drops of 10% sodium hypochlorite on fresh water agar for 20 s, removed, and placed on potato dextrose agar petri dishes amended with 25 μg/ml streptomycin. The isolates were kept at 24°C under continuous fluorescent lighting. After 9 days, black pycnidia were present, which produced smooth, hyaline, linear to curved, filiform conidia, 4 to 6 septate (mostly 6), 31.8 to 70.1 × 2.0 to 2.8 μm. The morphological descriptions and measurements were similar to those reported for Dolabra nepheliae (3). The nucleotide sequence of the internal transcribed spacer (ITS) region including ITS1, 5.8S, and ITS2 intergenic spacers was determined for strain P11-1-1and a BLAST analysis of the sequence (GenBank Accession No. JX566449) revealed 99% similarity (586/587 bp) with the sequence of D. nepheliae strain BPI 882442 on N. lappaceum from Honduras. Based on morphology and ITS sequencing, the fungus associated with the cankers was identified as the same causal agent reported on rambutan and pulasan (N. mutabile) from Malaysia (1), and later reported on rambutan and litchi in Hawaii and Puerto Rico (3). Upon closer observations of the diseased samples, sections of corky bark contained at least two larval insects. The beetles were identified as Corticeus sp. (Coleoptera: Tenebrionidae) and Araecerus sp. (Coleoptera: Anthribidae) by the USDA-ARS Systematic Entomology Laboratory (Beltsville, MD). A corky bark disease on the trunk and larger limbs of mature langsat trees in Florida was thought to be caused by Cephalosporium sp. with larvae (Lepidoptera: Tineidae) feeding on the diseased tissue (2). It is not known the extent to which either of the beetle species is associated with L. domesticum in Hawaii or if they play a role in the bark disorder. To our knowledge, this is the first report of Dolabra nepheliae being found on langsat in Hawaii. Effective management practices should be established to avoid potential production losses or spreading the disease to alternative hosts. References: (1) C. Booth and W. P. Ting. Trans. Brit. Mycol. Soc. 47:235, 1964. (2) J. Morton. Langsat. In: Fruits of Warm Climates, p. 201-203. Julia F. Morton, Miami, FL, 1987. (3) A. Y. Rossman et al. Plant Dis. 91:1685, 2007.
Symposium presentations

Krishnan S, Rohen JW, Lütjen-Drecoll E, Carmichael SW, Nicholson HD, Trotman P, et al.

Surg Radiol Anat, 2009 Sep;31 Suppl 1:43-8.
PMID: 27392490 DOI: 10.1007/BF03371484
Fulltext Assessment of variation in immunosuppressive pathway genes reveals TGFBR2 to be associated with risk of clear cell ovarian cancer

Hampras SS, Sucheston-Campbell LE, Cannioto R, Chang-Claude J, Modugno F, Dörk T, et al.

Oncotarget, 2016 10 25;7(43):69097-69110.
PMID: 27533245 DOI: 10.18632/oncotarget.10215

BACKGROUND: Regulatory T (Treg) cells, a subset of CD4+ T lymphocytes, are mediators of immunosuppression in cancer, and, thus, variants in genes encoding Treg cell immune molecules could be associated with ovarian cancer.
METHODS: In a population of 15,596 epithelial ovarian cancer (EOC) cases and 23,236 controls, we measured genetic associations of 1,351 SNPs in Treg cell pathway genes with odds of ovarian cancer and tested pathway and gene-level associations, overall and by histotype, for the 25 genes, using the admixture likelihood (AML) method. The most significant single SNP associations were tested for correlation with expression levels in 44 ovarian cancer patients.
RESULTS: The most significant global associations for all genes in the pathway were seen in endometrioid ( p = 0.082) and clear cell ( p = 0.083), with the most significant gene level association seen with TGFBR2 ( p = 0.001) and clear cell EOC. Gene associations with histotypes at p < 0.05 included: IL12 ( p = 0.005 and p = 0.008, serous and high-grade serous, respectively), IL8RA ( p = 0.035, endometrioid and mucinous), LGALS1 ( p = 0.03, mucinous), STAT5B ( p = 0.022, clear cell), TGFBR1 ( p = 0.021 endometrioid) and TGFBR2 ( p = 0.017 and p = 0.025, endometrioid and mucinous, respectively).
CONCLUSIONS: Common inherited gene variation in Treg cell pathways shows some evidence of germline genetic contribution to odds of EOC that varies by histologic subtype and may be associated with mRNA expression of immune-complex receptor in EOC patients.