scholarly journals Variations in macadamia varietal susceptibility to Phytophthora multivora and P. cinnamomi

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 109
Author(s):  
Olumide Jeff-Ego ◽  
Juliane Henderson ◽  
Bruce Topp ◽  
Andre Drenth ◽  
Olufemi Akinsanmi

Incidence of diseases caused by various Phytophthora spp. in macadamia is increasing worldwide, often resulting in severe yield loss and death of both juvenile and old macadamia trees. In Australia, P. cinnamomi and P. multivora has been identified to cause severe stem canker in macadamia orchards. Currently, various varietal improvement research programs on macadamia are underway, not only to obtain high-yielding and precocious macadamia germplasm but to develop macadamia genotypes with acceptable levels of tolerance/resistance to pests and diseases. In this study, we selected macadamia genotypes for their acceptable levels of tolerance/resistance to Phytophthora infection, after screening about 360 macadamia genotypes against to P. cinnamomi and P. multivora, using a rapid detached leaf and plant inoculation assays. These macadamia plant materials were collected from a major macadamia arboretum in Queensland. Our results revealed segregation of macadamia genotypes into two spectrum of susceptible and tolerant macadamia genotypes. Hence, strong representatives within the tolerant and susceptible spectrum were further investigated in order to understand if the basis of the differential response is driven by a variation in structural, physiological or genetic markers, following a challenge with Phytophthora spp. Our result revealed a marked variation in structural response during the infection process, between the selected susceptible, ‘HAES816’ and tolerant germplasm and ‘HAES344’. This information will provide evidence to support potential preferential selection of tolerant macadamia genotypes potentially useful for breeding against Phytophthora diseases. Further studies will characterize tolerant macadamia progenies to develop marker-assisted selection protocols for resistance, and explore defense mechanisms response.

2020 ◽  
Vol 31 (2) ◽  
pp. 88-92
Author(s):  
Vladimir Mikhailovich Koldaev ◽  
Artem Yurevich Manyakhin ◽  
Petr Semenovich Zorikov

AbstractThis paper aims at spectrophotometric determination of changes in stability of extractable anthocyanins during drying of plant materials depending on their color. Raw and dried colored parts of 50 plant species from 25 families were used for the study. The extracts were prepared over 95% ethanol acidified with hydrochloric acid (pH ~ 1). The absorption spectra were registered within the range of 210 to 680 nm. The extinction variability factor, coefficient of intensity absorption relative and generalized stability factor were used to determine the anthocyanin degradation. The highest values of the stability factor were obtained for the extracts from fruit shells of burgundy or violet color within the range of 0.934±0.024 to 0.973±0.024, while the extracts from flower petals of the same care featured the stability factor that was 1.19 to 1.44 times less. The values of the stability factor of the extracts from black, red and blue materials are 1.15 to 1.19 times, 1.74 to 2.48 times and 4.65 to 4.84 times less respectively than those of the extracts from violet-burgundy materials. It is appropriate to apply the spectrophotometric factors of anthocyanins stability used in this study to selection of promising plants for industrial cultivation as material of anthocyanin-containing herbal preparations. The most stable anthocyanins are those of burgundy-purple and black fruits.


2010 ◽  
Vol 5 (2) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Fabiola Domínguez ◽  
Marco Chávez ◽  
María Luisa Garduño-Ramírez ◽  
Víctor M. Chávez-Avila ◽  
Martín Mata ◽  
...  

An efficient protocol for the in vitro propagation of Magnolia dealbata Zucc., an important medicinal plant that is the source of the anxiolytic and anticancer compounds honokiol and magnolol, was established. This plant is wild-crafted, and conservationists have expressed concerns with regard to the sustainability of production. In the present work, two factors were found to be of importance for the regeneration of M. dealbata and the production of honokiol and magnolol. These factors were the type of explants and the combination and concentration of plant-growth regulators. Green, compact, nodular organogenic callus was obtained from leaf explants in a medium fortified with Murashige and Skoog salts and supplemented with 1.5 mg/L 2,4-dicholorophenoxyacetic acid and 1.5 mg/L kinetin. Shoot multiplication from callus cultures was achieved in the Murashige and Skoog (MS) medium with 1.5 mg/L thidiazuron (TDZ). Phenol secretion was controlled by the addition of 250 mg/L of activated charcoal. For rooting, shoots were transferred to MS medium supplemented with several auxins. After root induction, the plants were hardened in earthen pots containing sand, soil, and vermiculite. The contents of honokiol (HK) and magnolol (MG) were determined in different plant materials by high-performance liquid chromatography-diode-array detection techniques. This analysis revealed that the honokiol and magnolol content in aerial and underground parts of micropropagated M. dealbata were higher than that observed in wild plants (both 6 months old). Our results suggest that conservation of M. dealbata is possible by means of in vitro multiplication of leaf-derived callus. The usefulness of M. dealbata regeneration and production of HK and MG may be attributed to the proper selection of explant sourcing and identification of the correct growth medium to support adequate growth. This careful selection of explants and growth medium leads to a very useful source of plant material for pharmacological and phytomedicinal screening applications and, above all, would safeguard this plant species from the threat of extinction.


Radiocarbon ◽  
2014 ◽  
Vol 56 (02) ◽  
pp. 679-690
Author(s):  
V Caracuta ◽  
G Fiorentino ◽  
M Turchiano ◽  
G Volpe

Charred plant materials found in archaeological contexts are usually considered the most reliable remains for radiocarbon dating. Usually, seeds and fruits are preferred to wood fragments because their short lifecycle reduces the range of uncertainty of the14C measurement. A selection of short-lived samples, mainly from barley and wheat, from the Late Roman site of Faragola (SE Italy) were14C dated; however, the14C dates obtained were not always consistent with the chronology provided by other archaeological evidence. A careful analysis of all the macrobotanical remains found in each of the dated contexts provides insight into the origin of the plant material, helping to distinguish betweenin situand non-in situmaterial. The14C dates are reconsidered in the context of findings and the kind of material selected for dating. Using the archaeological context, a Bayesian model was employed to reduce the range of the calibrated date and thereby refine the chronology of the site on an absolute basis.


2011 ◽  
Vol 286 (41) ◽  
pp. 35742-35754 ◽  
Author(s):  
David J. Schnepple ◽  
Brett Shepard ◽  
Gary D. Bren ◽  
Nathan W. Cummins ◽  
Sekar Natesampillai ◽  
...  

Virus-host interactions are characterized by the selection of adaptive mechanisms by which to evade pathogenic and defense mechanisms, respectively. In primary T cells infected with HIV, HIV infection up-regulates TNF-related apoptosis inducing ligand (TRAIL) and death-inducing TRAIL receptors, but blockade of TRAIL:TRAIL receptor interaction does not alter HIV-induced cell death. Instead, HIV infection results in a novel splice variant that we call TRAIL-short (TRAIL-s), which antagonizes TRAIL-R2. In HIV patients, plasma TRAIL-s concentration increases with increasing viral load and renders cells resistant to TRAIL-induced death. Knockdown of TRAIL-s abrogates this resistance. We propose that TRAIL-s is a novel adaptive mechanism of apoptosis resistance acquired by HIV-infected cells to avoid their elimination by TRAIL-dependent effector mechanism.


2013 ◽  
Vol 103 (7) ◽  
pp. 733-740 ◽  
Author(s):  
Mayumi Egusa ◽  
Takuya Miwa ◽  
Hironori Kaminaka ◽  
Yoshitaka Takano ◽  
Motoichiro Kodama

The tomato pathotype of Alternaria alternata causes Alternaria stem canker on tomato depending upon the production of the host-specific AAL-toxin. Host defense mechanisms to A. alternata, however, are largely unknown. Here, we elucidate some of the mechanisms of nonhost resistance to A. alternata using Arabidopsis mutants. Wild-type Arabidopsis showed either no symptoms or a hypersensitive reaction (HR) when inoculated with both strains of AAL-toxin-producing and non-producing A. alternata. Yet, when these Arabidopsis penetration (pen) mutants, pen2 and pen3, were challenged with both strains of A. alternata, fungal penetration was possible. However, further fungal development and conidiation were limited on these pen mutants by postinvasion defense with HR-like cell death. Meanwhile, only AAL-toxin-producing A. alternata could invade lag one homologue (loh)2 mutants, which have a defect in the AAL-toxin resistance gene, subsequently allowing the fungus to complete its life cycle. Thus, the nonhost resistance of Arabidopsis thaliana to A. alternata consists of multilayered defense systems that include pre-invasion resistance via PEN2 and PEN3 and postinvasion resistance. However, our study also indicates that the pathogen is able to completely overcome the multilayered nonhost resistance if the plant is sensitive to the AAL-toxin, which is an effector of the toxin-dependent necrotrophic pathogen A. alternata.


2004 ◽  
Vol 70 (2) ◽  
pp. 991-998 ◽  
Author(s):  
Céline Lavire ◽  
Didier Blaha ◽  
Benoit Cournoyer

ABSTRACT Functional adaptations of σ70 transcriptional factors led to the emergence of several paralogous lineages, each one being specialized for gene transcription under particular growth conditions. Screening of a Frankia strain EaI-12 gene library by σ70 DNA probing allowed the detection and characterization of a novel actinomycetal primary (housekeeping) σ70 factor. Phylogenetic analysis positioned this factor in the RpoD cluster of proteobacterial and low-G+C-content gram-positive factors, a cluster previously free of any actinobacterial sequences. σ70 DNA probing of Frankia total DNA blots and PCR screening detected one or two rpoD-like DNA regions per species. rpoD matched the conserved region in all of the species tested. The other region was found to contain sigA, an alternative primary factor. sigA appeared to be strictly distributed among Frankia species infecting plants by the root hair infection process. Both genes were transcribed by Frankia strain ACN14a grown in liquid cultures. The molecular phylogeny of the σ70 family determined with Frankia sequences showed that the alternative actinomycetal factors and the essential ones belonged to the same radiation. At least seven distinct paralogous lineages were observed among this radiation, and gene transfers were detected in the HrdB actinomycetal lineage.


1987 ◽  
Vol 14 (6) ◽  
pp. 788-794
Author(s):  
Niels C. Lind

A design standard for structural glass in the limit state design format is currently being developed under the auspices of the Canadian General Standards Board. The standard will be calibrated to a target level of reliability expressed in terms of a reliability index. The selection of this reliability level presents some special problems because the loading is dynamic, the structural response is geometrically nonlinear, and the strength is highly dependent on time, size, and loading history. Selection of safety level so as to achieve a social and economic optimum is described. The optimum reliability index is 3.0, corresponding to a lifetime failure probability of 0.0014, when the social and economic cost of failure is between 15 and 70 times the initial cost. Optimal ranges of applicability over cost for a pair of importance factors (0.8 and 1.25) are also determined. Key words: glass, design, standard, code, calibration, reliability, optimization, importance factor.


Author(s):  
Alfita Rakhmandasari ◽  
Wayan Firdaus Mahmudy ◽  
Titiek Yulianti

<span>Kenaf plant is a fibre plant whose stem bark is taken to be used as raw material for making geo-textile, particleboard, pulp, fiber drain, fiber board, and paper. The presence of plant pests and diseases that attack causes crop production to decrease. The detection of pests and diseases by farmers may be a challenging task. The detection can be done using artificial intelligence-based method. Convolutional neural networks (CNNs) are one of the most popular neural network architectures and have been successfully implemented for image classification. However, the CNN method is still considered a long time in the process, so this method was developed into namely faster regional based convolution neural network (RCNN). As the selection of the input features largely determines the accuracy of the results, a pre-processing procedure is developed to transform the kenaf plant image into input features of faster RCNN. A computational experiment proves that the faster RCNN has a very short computation time by completing 10000 iterations in 3 hours compared to convolutional neural network (CNN) completing 100 iterations at the same time. Furthermore, Faster RCNN gets 77.50% detection accuracy and bounding box accuracy 96.74% while CNN gets 72.96% detection accuracy at 400 epochs. The results also prove that the selection of input features and its pre-processing procedure could produce a high accuracy of detection. </span>


Author(s):  
Alex Wegner ◽  
Louisa Wirtz ◽  
Thomas Leisen ◽  
Matthias Hahn ◽  
Ulrich Schaffrath

AbstractMagnaporthe oryzae is one of the most economically important phytopathogenic fungi, and is used as a model organism to study plant-pathogen interactions. To unravel the infection process, forward and reverse genetic approaches are essential, but are often hindered by the lack of a straightforward selection procedure for transformants. Here we report on the use of fenhexamid, an inhibitor of ergosterol biosynthesis, for selection of M. oryzae transformants. An allele of the sterol 3-ketoreductase gene of Fusarium fujikuroi (FfERG27), known to confer resistance to fenhexamid, has already been used successfully with transformants of Botrytis cinerea. Our results demonstrate that expression of the FfERG27 allele in M. oryzae also enables highly efficient selection of transformants on fenhexamid-containing media. The use of fenhexamid is an inexpensive alternative for selection as compared to commonly used antibiotics like hygromycin. No impact on growth and infection phenotypes of fenhexamid resistant M. oryzae mutants was detected, which underpins its usefulness for selecting M. oryzae transformants.


2020 ◽  
Vol 16 (4) ◽  
pp. 135
Author(s):  
DELIAH SESWITA

<p>ABSTRAK</p><p>Tanaman temulawak (Curcuma xanthorrhiza Roxb.) merupakansalah satu tanaman obat potensial unggulan yang memiliki khasiatmultifungsi. Rimpangnya yang berkhasiat obat mampu mengobati ber-bagai penyakit seperti kelainan pada hati/lever, kantong empedu, danpankreas. Adanya kecenderungan masyarakat ingin menggunakan pengo-batan dengan bahan alami, menjadikan permintaan benih temulawaksebagai bahan baku obat maupun industri jamu di Indonesia meningkatdengan pesat. Kondisi ini memberi peluang kepada petani sebagaipenyedia bahan tanaman. Upaya penyediaan bahan tanaman secara massaldalam waktu singkat serta bebas hama dan penyakit dapat dilakukanmelalui teknik kultur jaringan. Teknik ini dibatasi oleh tingginya biayaperbanyakan, di antaranya penggunaan bahan kimia. Oleh karena itu perludikaji penggunaan zat pengatur tumbuh (ZPT) yang berasal dari bahanalami (salah satunya adalah air kelapa) sebagai substitusi ZPT sintetik.Penelitian penggunaan air kelapa sebagai ZPT dilakukan di LaboratoriumKultur Jaringan Plasma Nutfah Pemuliaan dan Perbenihan, BalaiPenelitian Tanaman Obat dan Aromatik Bogor, dari bulan Mei sampaidengan bulan Desember 2009. Eksplan berasal dari tunas temulawak sterilhasil perbanyakan sebelumnya. Media yang digunakan adalah mediaMurashige and Skoog (MS) yang dikombinasikan dengan beberapa tarafkonsentrasi air kelapa (0, 5, 10, 15, dan 20%) sebagai substitusi ZPT danair kelapa dengan memakai millipore. Media dibuat padat, sebagaipembanding pada media MS + ZPT kimia yaitu BA1,5 mg/l. Percobaanmenggunakan rancangan acak lengkap dengan 10 ulangan. Parameteryang diuji adalah jumlah tunas, jumlah daun dan jumlah akar. Hasilpenelitian menunjukkan, tanpa komponen kimia, dengan penambah airkelapa pada berbagai konsentrasi pada media dasar MS, berhasilmembentuk tunas, daun dan akar. Jumlah tunas terbanyak didapat padakombinasi media dengan penambahan air kelapa 15% sebanyak 3,4 tunas,jumlah daun 2,2 daun serta jumlah akar terbanyak yaitu sebanyak 13,2akar pada umur 2 minggu. Pada kombinasi media dengan memakaimillipore, tunas terbanyak hanya 2,6 tunas, tetapi tidak berbeda nyatadengan perlakuan kontrol MS + BA 1,5 mg/l, yaitu sama-sama memiliki2,6 tunas, 3,6 daun, dan 15,4 akar.</p><p>Kata kunci : Curcuma xanthorrhiza Roxb., in vitro, air kelapa, zatpengatur tumbuh, multiplikasi in vitro</p><p>ABSTRACT</p><p>The use of Coconut Water as Growth Regulator onMultiplication of Java Turmeric Buds (Curcumaxanthorrhiza Roxb. ) in vitro</p><p>Java turmeric (Curcuma xanthorrhiza Roxb.) is a potentialmedicinal plant which has many uses. Its rhizome has efficacy to curevarious diseases such as disorder on lever, gall bladder and pancreas.There is a tendency that people want to use therapy by natural materials,increases demand of turmeric seed as raw material of medicine industry inIndonesia. This condition provides a chance to farmers as supplier of plantmaterials. However, up to now, the high need of plant materials causes thelimitation of supply so that their alternatives are needed for providing plantmaterials in maximum number. The part of plant material provision in highnumber and in a short time and free from pests and diseases can beconducted through tissue culture technique. However, this technique islimited by the high cost of multiplication, among others the use ofchemical materials. Therefore, the use of growth regulator originated fromnatural material as substitution of synthetic growth regulator need to beassessed, one of them is coconut water. The experiment was carried out atthe laboratory of Tissue Culture, Germ Plasm, and Plant Breeding,Indonesia for Medicinal and Aromatic Crop Research Institute, Bogorfrom May to December 2009. Explants originated from sterile turmericshoots, product of previous multiplication. Media used was Murashige andSkoog (MS) combined with several concentration levels of coconut water( 0; 5; 10; 15, and 20%) as substitution of growth regulator and coconutwater by using millipore. Solid media was used, as comparison on mediaof chemical MS + was BA1.5 mg/l. The experiment was arranged incompletely randomized design with 10 replications. Parameters observedwere the numbers of shoots, leaves and roots. Results showed that withoutchemical component, by addition of coconut water on variousconcentrations on based media of MS, produced shoots, leaves and roots.The highest shoot number obtained on combination of media and additionof coconut water 15% as many as 3.4 shoots, with the number of leaves2.2 leaves at the age of 2 weeks and the highest roots formed on 15 %coconut water as many as 13.2 roots. Whereas on combination of mediawith millipore, the highest shoots were only 2.6 shoots, however it was notsignificantly different from treatment of control MS + BA 1.5 mg/l, itproduced 2.6 shoots,3.6 leaves and 15.4 roots.</p><p>Key words : Curcuma xanthorrhiza Roxb., in vitro, coconut water,growth regulator, multiplication in vitro</p>


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