The effect of crown pruning and induction of Acremonium sp. on agarwood formation in Gyrinops caudata in West Papua, Indonesia

Auri A, Faridah E, Sumardi, Hardiwinoto S. 2021. The effect of crown pruning and induction of Acremonium sp. on agarwood formation in Gyrinops caudata in West Papua, Indonesia. Biodiversitas 22: 2604-2611. Agarwood-producing trees have been planted by the community, but have currently not produced agarwood resin. This research examines the crown pruning effect and fungi inoculation effectivity on the formation of agarwood resin in Gyrinops caudata. The environmental modification was also ascertained based on the real environmental situation in natural forests. Furthermore, it was assumed that environmental conditions significantly influenced the growth, G. caudata tree association, and fungi infection. This method involved the tree crown cover modification. Tree crown was categorized into three different classes, i.e. dense crown (no pruning); moderate (pruning 25%), and sparse (pruning 50%). The results showed that inoculating fungi of Acremonium sp. to infection coverage area after three months produced the best results, due to Fcount 79.671. However, crown prunings obtained through heavy, moderate and non-pruning did not show any effect on stem infection spread. In the sixth month, it was observed that the fungi inoculation factor of Acremonium sp. had a significant effect on infection spread formation by Fcount of 168.894. The change in wood internal tissue also had a highly significant effect as depicted by Fcount 461.516. The fragrance level treatment also showed a considerable effect with Fcount 290.385.

Sample-Pooling Strategy for SARS-CoV-2 Detection among Students and Staff of the University of Sannio

Since the beginning of the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic, it has been clear that testing large groups of the population was the key to stem infection and prevent the effects of the coronavirus disease of 2019, mostly among sensitive patients. On the other hand, time and cost-sustainability of virus detection by molecular analysis such as reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) may be a major issue if testing is extended to large communities, mainly asymptomatic large communities. In this context, sample-pooling and test grouping could offer an effective solution. Here we report the screening on 1195 oral-nasopharyngeal swabs collected from students and staff of the Università degli Studi del Sannio (University of Sannio, Benevento, Campania, Italy) and analyzed by an in-house developed multiplex RT-qPCR for SARS-CoV-2 detection through a simple monodimensional sample pooling strategy. Overall, 400 distinct pools were generated and, within 24 h after swab collection, five positive samples were identified. Out of them, four were confirmed by using a commercially available kit suitable for in vitro diagnostic use (IVD). High accuracy, sensitivity and specificity were also determined by comparing our results with a reference IVD assay for all deconvoluted samples. Overall, we conducted 463 analyses instead of 1195, reducing testing resources by more than 60% without lengthening diagnosis time and without significant losses in sensitivity, suggesting that our strategy was successful in recognizing positive cases in a community of asymptomatic individuals with minor requirements of reagents and time when compared to normal testing procedures.

Virulence tests of Neofusicoccum parvum, Lasiodiplodia theobromae, and Phytophthora palmivora on Theobroma cacao

Neofusicoccum parvum is a recently reported pathogen affecting Theobroma cacao L., and has been isolated from symptomatic pods on Oahu and Hawaii Islands. Determining infection routes and virulence are essential for assessing the impact of N. parvum on cacao production and developing effective disease management strategies. Infection routes were determined by inoculating unwounded stems and pods with six isolates of N. parvum alongside Lasiodiplodia theobromae and Phytophthora palmivora. Fifty percent of unwounded stems inoculated with P. palmivora developed lesions, but only a single lesion developed following inoculation with N. parvum (isolate H44). L. theobromae and the remaining N. parvum isolates did not induce lesion development on unwounded stems. In contrast, all N. parvum and L. theobromae isolates produced lesions on 40–100% of unwounded pods of GNV 164 and GNV 360. Low incidences of infection were observed in unwounded pods of ICS 95 (0–66.7%), SHRS 21 (0–75%), and SHRS 33 (0–20%). On wounded pods, all pathogen species produced similar size lesions, ranging from 1.90 to 7.60 cm four days after inoculation. Results from this study show that all three species can produce high rates of pod infection on some clones in the absence of wounds, but stem infection is less likely. In addition, this is the first report of L. theobromae infecting cacao pods and P. palmivora infecting stems in the absence of wounds.

Resistance of New Zealand Provenance Leptospermum scoparium, Kunzea robusta, Kunzea linearis, and Metrosideros excelsa to Austropuccinia psidii

Resistance to the pandemic strain of Austropuccinia psidii was identified in New Zealand provenance Leptospermum scoparium, Kunzea robusta, and K. linearis plants. Only 1 Metrosideros excelsa-resistant plant was found (of the 570 tested) and no resistant plants of either Lophomyrtus bullata or L. obcordata were found. Three types of resistance were identified in Leptospermum scoparium. The first two, a putative immune response and a hypersensitive response, are leaf resistance mechanisms found in other myrtaceous species while on the lateral and main stems a putative immune stem resistance was also observed. Both leaf and stem infection were found on K. robusta and K. linearis plants as well as branch tip dieback that developed on almost 50% of the plants. L. scoparium, K. robusta, and K. linearis are the first myrtaceous species where consistent infection of stems has been observed in artificial inoculation trials. This new finding and the first observation of significant branch tip dieback of plants of the two Kunzea spp. resulted in the development of two new myrtle rust disease severity assessment scales. Significant seed family and provenance effects were found in L. scoparium, K. robusta, and K. linearis: some families produced significantly more plants with leaf, stem, and (in Kunzea spp.) branch tip dieback resistance, and provenances provided different percentages of resistant families and plants. The distribution of the disease symptoms on plants from the same seed family, and between plants from different seed families, suggested that the leaf, stem, and branch tip dieback resistances were the result of independent disease resistance mechanisms.

A module to simulate the impact of western gall rust (Cronartium harknessii) on merchantable volume and lumber yields for lodgepole pine (Pinus contorta var. latifolia) stands in British Columbia

Western gall rust (Cronartium harknessii (J.P. Moore) E. Meinecke) is a pathogen that affects lodgepole pine (Pinus contorta Douglas ex Loudon var. latifolia Engelm. ex S. Watson) and has the potential to reduce lumber product yields derived from stands managed for the commercial production of timber. A dataset containing repeated measurements from 7775 trees located within the province of British Columbia, Canada, was used to develop equations that predict annual rates of stem infection, post-infection mortality, and the location of large stem galls. Results showed that annual rates of infection peaked between 3 and 5 years following stand establishment. Few new infections were predicted to occur beyond the stand age of 15 years. For an individual tree, the probability of first infection increased as its height increased relative to stand top height. The rate of mortality increased with the number of stem infections and was highest among trees infected within the first 3 years following planting. Mortality rates decreased thereafter, with many trees likely to survive to rotation. The equations predicting rust incidence and mortality were added to the Tree and Stand Simulator (TASS), an individual-tree growth model used within the province. A final equation predicting the location of large galls was added and allows TASS to account for losses due to the removal of stem defects during lumber manufacturing.

Resistance mechanisms of white jabon seedlings (Anthocephalus cadamba) against Botryodiplodia theobromae causing dieback disease

Yanti LA, Achmad, Khumaida N. 2018. Resistance mechanisms of white jabon seedlings (Anthocephalus cadamba) againstBotryodiplodia theobromae causing dieback disease. Biodiversitas 19: 1441-1450. Anthocephalus cadamba (Roxb.) Miq. seedlings arethe most preferred plant for the nursery as they serve a lot of benefits and can be used as shading trees, reforestation, plywood, pulp,paper, and traditional medicines. Further, those benefits can increase the economic value of this plant. The main problem in the nurseryof forestry plants is pest and disease attacks, one of which is dieback disease. The dieback disease is caused by Botryodiplodiatheobromae Pat. that may lead death of the host plant. Every plant has its resistance mechanism toward pathogen attacks. This researchaimed: (1) to study B. theobromae attack through wounded and non-wounded stem infection methods on white jabon seedlings; (2) tostudy the resistance mechanisms of white jabon seedlings both structural and biochemical resistance against B. theobromae. This studyemployed a factorial treatment design laid out in a completely randomized design. The structural resistance was determined by studyingthe microscopic appearance of the white jabon seedlings’ stem by using a scanning electron microscope. Meanwhile, the biochemicalresistance was determined by characterizing the chemical compounds of white jabon seedlings' stem using phytochemistry analysis. Theresult showed that the disease incidence of the control (inoculated without pathogen isolate) and the inoculated (inoculated withpathogen isolate) seedlings were, respectively, 0% and 100% (with wounded stem) and 0% and 30% (non-wounded). The diseaseseverity of control and inoculated seedlings were 0% and 62% (with wounded stem) and 0% and 12% (non-wounded stem),respectively. The incubation period of wounded and non-wounded stems on inoculated seedlings (inoculated with pathogen isolate) wasone day after inoculation with the numeric values (disease scores) of 4 and 2, respectively. White jabon seedlings had necrotic resistanceas structural resistance mechanism against the pathogen attack. White jabon seedlings also contained secondary metabolites such asalkaloids, flavonoid, phenyl hydroquinone, tannin, saponin, and steroids. The biochemical resistance of white jabon seedling afterpathogen attacks was shown by the increase of accumulated phenolic compounds such as flavonoid and tannin.

Burkholderia pseudomallei Rapidly Infects the Brain Stem and Spinal Cord via the Trigeminal Nerve after Intranasal Inoculation

Infection withBurkholderia pseudomalleicauses melioidosis, a disease with a high mortality rate (20% in Australia and 40% in Southeast Asia). Neurological melioidosis is particularly prevalent in northern Australian patients and involves brain stem infection, which can progress to the spinal cord; however, the route by which the bacteria invade the central nervous system (CNS) is unknown. We have previously demonstrated thatB. pseudomalleican infect the olfactory and trigeminal nerves within the nasal cavity following intranasal inoculation. As the trigeminal nerve projects into the brain stem, we investigated whether the bacteria could continue along this nerve to penetrate the CNS. After intranasal inoculation of mice,B. pseudomalleicaused low-level localized infection within the nasal cavity epithelium, prior to invasion of the trigeminal nerve in small numbers.B. pseudomalleirapidly invaded the trigeminal nerve and crossed the astrocytic barrier to enter the brain stem within 24 h and then rapidly progressed over 2,000 μm into the spinal cord. To rule out that the bacteria used a hematogenous route, we used a capsule-deficient mutant ofB. pseudomalleithat does not survive in the blood and found that it also entered the CNS via the trigeminal nerve. This suggests that the primary route of entry is via the nerves that innervate the nasal cavity. We found that actin-mediated motility could facilitate initial infection of the olfactory epithelium. Thus, we have demonstrated thatB. pseudomalleican rapidly infect the brain and spinal cord via the trigeminal nerve branches that innervate the nasal cavity.

Hard pine stem rusts on lodgepole pine at a site-preparation study in sub-boreal British Columbia: effects over 24 years

Site preparation can improve lodgepole pine (Pinus contorta var. latifolia Engelm. ex S. Watson) survival and growth; however, we lack information regarding possible interactions between treatment effects and the impacts of western gall rust (Endocronartium harknessii (J.P. Moore) Y. Hirats.) and comandra blister rust (Cronartium comandrae Peck). Mechanical and burning techniques examined over 24 years at a sub-boreal British Columbia site did not significantly increase rust infection rates or characteristics relative to an untreated control. Most infection occurred before age 10 years and at heights <2 m. By age 24 years, 22% and 10% of pine had sustained at least one western gall rust or comandra blister rust stem infection, respectively, but only 4% of western gall rust infected trees were dead, compared with 60% of comandra blister rust infected trees. Exploratory regression analysis of the relationship between tree volume and percent stem encirclement and infection height suggested that volume of 24-year-old pine infected with western gall rust averaged 8% less than the corresponding volume of uninfected trees. Over 24 years, estimated stand-level, rust-related volume loss was 8.4%, with the majority due to mortality from comandra blister rust. One-fifth of estimated volume loss was provisionally attributed to growth reductions among live western gall rust infected pine.