Reflectance of Sooty Mold Fungus on Citrus Leaves Over the 2.5 to 40-Micrometer Wavelength Interval

The spotted lanternfly (Lycorma delicatula) is an invasive species first detected in 2014. The insect feeds on plants causing severe damage in vineyards such as the occurrence of sooty mold fungus that impairs leaf photosynthesis. Currently, there is extensive research on how to track and ultimately prevent the spread of this species. It lays eggs that persist through the winter, while the adults die out, which presents a unique opportunity to enter infested or suspected infested areas to begin quarantine and management of the spread while the species is dormant. Detection dogs may be a tool that can be used to search out the spotted lanternfly egg masses during this overwintering period, however it is not known whether dogs can detect any specific odor from the spotted lanternfly eggs. Moreover, as the eggs are only available during certain times of the year, and hatch based on temperature, finding training aids for the dogs could prove difficult. In this study, we investigated whether three detection dogs could learn the odor from dead spotted lanternfly egg masses and if so, whether that would allow them to recognize live spotted lanternfly egg masses. We found that dogs could be trained to find dead spotted lanternfly egg masses, and could learn to ignore relevant controls, with high levels of sensitivity and specificity (up to 94.6% and 92.8%, respectively). Further, we found that after the training, dogs could find live spotted lanternfly egg masses without additional training and returned to previous levels of sensitivity and specificity within a few sessions. Coded videos of training and testing sessions showed that dogs spent more time at the egg masses than at controls, as expected from training. These results suggest that dead spotted lanternfly egg masses could be a useful training aid for spotted lanternfly detection dogs.

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Effect of Adjuvants on Oxytetracycline Uptake upon Foliar Application in Citrus

Antibiotics ◽

10.3390/antibiotics9100677 ◽

2020 ◽

Vol 9 (10) ◽

pp. 677

Author(s):

Nabil Killiny ◽

Faraj Hijaz ◽

Pedro Gonzalez-Blanco ◽

Shelley E. Jones ◽

Myrtho O. Pierre ◽

...

Keyword(s):

Foliar Application ◽

Foliar Spray ◽

Bacterial Pathogen ◽

Water Addition ◽

Candidatus Liberibacter ◽

Citrus Huanglongbing ◽

Liberibacter Asiaticus ◽

Trunk Injection ◽

Citrus Leaves ◽

Target Effects

Recently in Florida, foliar treatments using products with the antibiotics oxytetracycline and streptomycin have been approved for the treatment of citrus Huanglongbing (HLB), which is caused by the putative bacterial pathogen ‘Candidatus Liberibacter asiaticus’. Herein, we assessed the levels of oxytetracycline and ‘Ca. L. asiaticus’ titers in citrus trees upon foliar applications with and without a variety of commercial penetrant adjuvants and upon trunk injection. The level of oxytetracycline in citrus leaves was measured using an oxytetracycline ELISA kit and ‘Ca. L. asiaticus’ titer was measured using quantitative PCR. Low levels of oxytetracycline were taken up by citrus leaves after foliar sprays of oxytetracycline in water. Addition of various adjuvants to the oxytetracycline solution showed minimal effects on its uptake by citrus leaves. The level of oxytetracycline in leaves from trunk-injected trees was higher than those treated with all foliar applications. The titer of ‘Ca. L. asiaticus’ in the midrib of leaves from trees receiving oxytetracycline by foliar application was not affected after four days and thirty days of application, whereas the titer was significantly reduced in oxytetracycline-injected trees thirty days after treatment. Investigation of citrus leaves using microscopy showed that they are covered by a thick lipidized cuticle. Perforation of citrus leaf cuticle with a laser significantly increased the uptake of oxytetracycline, decreasing the titer of ‘Ca. L. asiaticus’ in citrus leaves upon foliar application. Taken together, our findings indicate that trunk injection is more efficient than foliar spray even after the use of adjuvants. Our conclusion could help in setting useful recommendations for the application of oxytetracycline in citrus to improve tree health, minimize the amount of applied antibiotic, reduce environmental exposure, and limit off-target effects.

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Identification and function prediction of iron-deficiency-responsive microRNAs in citrus leaves

3 Biotech ◽

10.1007/s13205-021-02669-z ◽

2021 ◽

Vol 11 (3) ◽

Author(s):

Long-Fei Jin ◽

Rajesh Yarra ◽

Xin-Xing Yin ◽

Yong-Zhong Liu ◽

Hong-Xing Cao

Keyword(s):

Iron Deficiency ◽

Function Prediction ◽

Citrus Leaves ◽

And Function

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Characterization of microbial antifreeze protein with intermediate activity suggests that a bound-water network is essential for hyperactivity

Scientific Reports ◽

10.1038/s41598-021-85559-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

N. M.-Mofiz Uddin Khan ◽

Tatsuya Arai ◽

Sakae Tsuda ◽

Hidemasa Kondo

Keyword(s):

Crystal Structure ◽

Basal Plane ◽

Molecular Mechanisms ◽

Bound Water ◽

Hydrophobic Hydration ◽

Water Network ◽

Molecular Scaffold ◽

Intermediate Activity ◽

Mold Fungus ◽

Antifreeze Activity

AbstractAntifreeze proteins (AFPs) inhibit ice growth by adsorbing onto specific ice planes. Microbial AFPs show diverse antifreeze activity and ice plane specificity, while sharing a common molecular scaffold. To probe the molecular mechanisms responsible for AFP activity, we here characterized the antifreeze activity and crystal structure of TisAFP7 from the snow mold fungus Typhula ishikariensis. TisAFP7 exhibited intermediate activity, with the ability to bind the basal plane, compared with a hyperactive isoform TisAFP8 and a moderately active isoform TisAFP6. Analysis of the TisAFP7 crystal structure revealed a bound-water network arranged in a zigzag pattern on the surface of the protein’s ice-binding site (IBS). While the three AFP isoforms shared the water network pattern, the network on TisAFP7 IBS was not extensive, which was likely related to its intermediate activity. Analysis of the TisAFP7 crystal structure also revealed the presence of additional water molecules that form a ring-like network surrounding the hydrophobic side chain of a crucial IBS phenylalanine, which might be responsible for the increased adsorption of AFP molecule onto the basal plane. Based on these observations, we propose that the extended water network and hydrophobic hydration at IBS together determine the TisAFP activity.

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Cyclophilin BcCyp2 Regulates Infection-Related Development to Facilitate Virulence of the Gray Mold Fungus Botrytis cinerea

International Journal of Molecular Sciences ◽

10.3390/ijms22041694 ◽

2021 ◽

Vol 22 (4) ◽

pp. 1694

Author(s):

Jiao Sun ◽

Chen-Hao Sun ◽

Hao-Wu Chang ◽

Song Yang ◽

Yue Liu ◽

...

Keyword(s):

Botrytis Cinerea ◽

Cyclic Adenosine Monophosphate ◽

Adenosine Monophosphate ◽

Gray Mold ◽

Gene Encoding ◽

Histone 3 ◽

Mold Fungus ◽

Related Development ◽

Hyphal Morphology ◽

Cellular Components

Cyclophilin (Cyp) and Ca2+/calcineurin proteins are cellular components related to fungal morphogenesis and virulence; however, their roles in mediating the pathogenesis of Botrytis cinerea, the causative agent of gray mold on over 1000 plant species, remain largely unexplored. Here, we show that disruption of cyclophilin gene BcCYP2 did not impair the pathogen mycelial growth, osmotic and oxidative stress adaptation as well as cell wall integrity, but delayed conidial germination and germling development, altered conidial and sclerotial morphology, reduced infection cushion (IC) formation, sclerotial production and virulence. Exogenous cyclic adenosine monophosphate (cAMP) rescued the deficiency of IC formation of the ∆Bccyp2 mutants, and exogenous cyclosporine A (CsA), an inhibitor targeting cyclophilins, altered hyphal morphology and prevented host-cell penetration in the BcCYP2 harboring strains. Moreover, calcineurin-dependent (CND) genes are differentially expressed in strains losing BcCYP2 in the presence of CsA, suggesting that BcCyp2 functions in the upstream of cAMP- and Ca2+/calcineurin-dependent signaling pathways. Interestingly, during IC formation, expression of BcCYP2 is downregulated in a mutant losing BcJAR1, a gene encoding histone 3 lysine 4 (H3K4) demethylase that regulates fungal development and pathogenesis, in B. cinerea, implying that BcCyp2 functions under the control of BcJar1. Collectively, our findings provide new insights into cyclophilins mediating the pathogenesis of B. cinerea and potential targets for drug intervention for fungal diseases.

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Automated Detection of Tetranychus urticae Koch in Citrus Leaves Based on Colour and VIS/NIR Hyperspectral Imaging

Agronomy ◽

10.3390/agronomy11051002 ◽

2021 ◽

Vol 11 (5) ◽

pp. 1002

Author(s):

María Gyomar Gonzalez-Gonzalez ◽

Jose Blasco ◽

Sergio Cubero ◽

Patricia Chueca

Keyword(s):

Hyperspectral Imaging ◽

Tetranychus Urticae ◽

Visual Inspection ◽

Vision System ◽

Automated Detection ◽

Nutritional Deficiencies ◽

Phyllocnistis Citrella ◽

Mature Leaves ◽

Citrus Leaves ◽

Tetranychus Urticae Koch

Tetranychus urticae Koch is an important citrus pest that produces chlorotic spots on the leaves and scars on the fruit of affected trees. It is detected by visual inspection of the leaves. This work studies the potential of colour and hyperspectral imaging (400–1000 nm) under laboratory conditions as a fast and automatic method to detect the damage caused by this pest. The ability of a traditional vision system to differentiate this pest from others, such as Phyllocnistis citrella, and other leaf problems such as those caused by nutritional deficiencies, has been studied and compared with a more advanced hyperspectral system. To analyse the colour images, discriminant analysis has been used to classify the pixels as belonging to either a damaged or healthy leaves. In contrast, the hyperspectral images have been analysed using PLS DA. The rate of detection of the damage caused by T. urticae with colour images reached 92.5%, while leaves that did not present any damage were all correctly identified. Other problems such as damage by P. citrella were also correctly discriminated from T. urticae. Moreover, hyperspectral imaging allowed damage caused by T. urticae to be discriminated from healthy leaves and to distinguish between recent and mature leaves, which indicates whether it is a recent or an older infestation. Furthermore, good results were achieved in the discrimination between damage caused by T. urticae, P. citrella, and nutritional deficiencies.

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Effect of Petroleum Oil Spray on Photosynthesis and Respiration in Citrus Leaves

PLANT PHYSIOLOGY ◽

10.1104/pp.27.2.269 ◽

1952 ◽

Vol 27 (2) ◽

pp. 269-278 ◽

Cited By ~ 24

Author(s):

R. T. Wedding ◽

L. A. Riehl ◽

W. A. Rhoads

Keyword(s):

Citrus Leaves ◽

Photosynthesis And Respiration ◽

Petroleum Oil

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Simultaneous determination of nickel, lead, zinc, and copper in citrus leaves and rice flour by liquid chromatography with hexamethylenedithiocarbamate extraction

Analytical Chemistry ◽

10.1021/ac00289a011 ◽

1985 ◽

Vol 57 (12) ◽

pp. 2219-2222 ◽

Cited By ~ 63

Author(s):

Susumu. Ichinoki ◽

Mitsuru. Yamazaki

Keyword(s):

Liquid Chromatography ◽

Simultaneous Determination ◽

Rice Flour ◽

Determination Of Nickel ◽

Lead Zinc ◽

Citrus Leaves ◽

Nickel Lead

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Haustorial development of Peronospora tabacina infecting Nicotiana tabacum

Canadian Journal of Botany ◽

10.1139/b83-388 ◽

1983 ◽

Vol 61 (12) ◽

pp. 3444-3453 ◽

Cited By ~ 3

Author(s):

R. N. Trigiano ◽

C. G. Van Dyke ◽

H. W. Spurr Jr.

Keyword(s):

Cell Wall ◽

Toluidine Blue ◽

Mesophyll Cell ◽

Wall Layer ◽

Peronospora Tabacina ◽

Host Cytoplasm ◽

Transmission Electron ◽

Mold Fungus ◽

Host Cell Wall ◽

Hyphal Wall

The development of haustoria in tobacco by the blue-mold fungus Peronospora tabacina was examined using light, scanning, and transmission electron microscopy. Electron-lucent, callose-like appositions were observed between the host plasmalemma and the host mesophyll cell wall prior to haustorial penetration. An electron-opaque penetration matrix was present between the apposition and the host cell wall. The intercellular hyphal wall consisted of two layers which differed in staining quality. The haustorial wall was also two layered, but was primarily composed of and continuous with the inner wall layer of the intercellular hypha. Haustoria were either finger-like or branched and were encased with callose-like material. Most encasements were thickened at the proximal regions of haustoria but were thinner along the distal portions. Vesicles were present in host cytoplasm and were occasionally attached to the invaginated host plasmalemma. These vesicles might contribute to the deposition of the encasement material. The encasement stained positively for callose using aniline blue; calcofluor and toluidine blue O tests for cellulose were inconclusive, and lignin was not detected using toluidine blue O or phloroglucinol–HCl.

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