Herbaceous plants in the understory of a pitch canker-affected Pinus radiata plantation are endophytically infected with Fusarium circinatum

[EN] Fusarium circinatum was recently detected as an endophyte in grasses causing no apparent damage. Our goal was to describe the endophytic colonization of herbaceous host plants growing in a plantation of Pinus radiata with symptoms of pitch canker disease, which may act as a reservoir of inoculum. We detected the fungus in five species of dicot families (Asteraceae, Lamiaceae, Rosaceae), in addition to two species in the Poaceae. The fungus was found in the aerial part of non-symptomatic hosts, so we describe E circinatum as an endophyte that is mainly transmitted by spores through the air. It was also detected in Hypochaeris radicata seeds, suggesting the potential occurrence of vertical transmission. An analysis of microsatellite markers showed a unique haplotype regardless of whether the isolates' origin was pine cankers or non-symptomatic herbaceous plants. Thus, the same genotype can adopt a pathogenic or endophytic lifestyle. We conclude that non -symptomatic plants can act as reservoirs of inoculum: pine seedlings can be infeded from senescent tissue of non-symptomatic hosts colonized by the fungus. (C) 2017 Elsevier Ltd and British Mycological Society. All rights reserved.We acknowledge Maite Morales Clemente for her excellent technical assistance and Inigo Zabalgogeazcoa for his helpful suggestions. Laura Hernandez was supported by a fellowship from INIA (FPI-INIA). Financial support for this research was provided by projects RTA2012-00015-C02-01 and RTA2013-00048-C03-01 (Programa Estatal I + D + i, INIA, Spain).Hernandez-Escribano, L.; Iturritxa, E.; Elvira-Recuenco, M.; Berbegal Martinez, M.; Campos, J.; Renobales, G.; García, I.... (2018). Herbaceous plants in the understory of a pitch canker-affected Pinus radiata plantation are endophytically infected with Fusarium circinatum. Fungal Ecology. 32:65-71. https://doi.org/10.1016/j.funeco.2017.12.001S65713

Genomic Organization and Expression Demonstrate Spatial and Temporal Hox Gene Colinearity in the Lophotrochozoan Capitella sp. I

Hox genes define regional identities along the anterior–posterior axis in many animals. In a number of species, Hox genes are clustered in the genome, and the relative order of genes corresponds with position of expression in the body. Previous Hox gene studies in lophotrochozoans have reported expression for only a subset of the Hox gene complement and/or lack detailed genomic organization information, limiting interpretations of spatial and temporal colinearity in this diverse animal clade. We studied expression and genomic organization of the single Hox gene complement in the segmented polychaete annelid Capitella sp. I. Total genome searches identified 11 Hox genes in Capitella, representing 11 distinct paralog groups thought to represent the ancestral lophotrochozoan complement. At least 8 of the 11 Capitella Hox genes are genomically linked in a single cluster, have the same transcriptional orientation, and lack interspersed non-Hox genes. Studying their expression by situ hybridization, we find that the 11 Capitella Hox genes generally exhibit spatial and temporal colinearity. With the exception of CapI-Post1, Capitella Hox genes are all expressed in broad ectodermal domains during larval development, consistent with providing positional information along the anterior–posterior axis. The anterior genes CapI-lab, CapI-pb, and CapI-Hox3 initiate expression prior to the appearance of segments, while more posterior genes appear at or soon after segments appear. Many of the Capitella Hox genes have either an anterior or posterior expression boundary coinciding with the thoracic–abdomen transition, a major body tagma boundary. Following metamorphosis, several expression patterns change, including appearance of distinct posterior boundaries and restriction to the central nervous system. Capitella Hox genes have maintained a clustered organization, are expressed in the canonical anterior–posterior order found in other metazoans, and exhibit spatial and temporal colinearity, reflecting Hox gene characteristics that likely existed in the protostome–deuterostome ancestor

First Report of Fusarium circinatum, Causal Agent of Pitch Canker Disease, from the Roots of Mature Aleppo Pines in California

A rapid decline of Aleppo pines was observed in the parking lot of the Legoland amusement park in San Diego Co., CA. Although Aleppo pine is a known host for Fusarium circinatum, this is the first report describing resin-soaked sapwood lesions in the roots of mature trees. Previous reports on root infections regarded seedlings. The infestation in this location may have begun with infected roots in planted saplings. The persistent infestation at Legoland represents a significant source of inoculum for this pathogen exotic to California

Variation in Rates of Spore Deposition of Fusarium circinatum, the Causal Agent of Pine Pitch Canker, Over a 12-Month-Period at Two Locations in Northern California

Patterns of spore deposition by Fusarium circinatum, the causal agent of pine pitch canker (PPC) of Monterey pine (Pinus radiata) and other conifers, were studied between May 2003 and April 2004 at two sites in Northern California using a novel spore trapping method combined with a real-time polymerase chain reaction (PCR) approach. At each study site, two plots were sampled by placing spore traps at 100 m intervals along transects 600 m in length. The air was sampled continuously by exchanging the spore traps every 2 weeks. The spore deposition rate (DR), ranged from 0 to 1.3 × 105 spores m–2. Spores were detected throughout the year, with higher trapping frequencies (TF) during the rainy season (November to April), than during the dry season (May to October). The detection of spores on traps at distances larger than 200 m from any Monterey pine, suggests at least midrange aerial dispersal. Finally, different inoculum loads were associated with trees displaying different levels of disease symptoms, suggesting infectiousness of the pathogen varies as the disease progresses. This study represents one of the first documenting continuous inoculum pressure values over an entire year for a forest pathogen, and provides important epidemiological information that will be invaluable in the development of disease progression models