scholarly journals Temporal Increase and Spatial Distribution of Sugarcane Yellow Leaf and Infestations of the Aphid Vector, Melanaphis sacchari

Plant Disease ◽  
2008 ◽  
Vol 92 (4) ◽  
pp. 607-615 ◽  
Author(s):  
C. D. McAllister ◽  
J. W. Hoy ◽  
T. E. Reagan

Yellow leaf, caused by Sugarcane yellow leaf virus (ScYLV), is a potentially important disease of sugarcane first found in Louisiana during 1996. A survey during 2002 determined that ScYLV infection was present in all sugarcane-production areas of Louisiana. Virus was detected in 48% of 42 fields, and incidence averaged 15% in these fields. Disease progress curves determined in four fields during two growing seasons indicated that the greatest temporal increase of virus infection occurred during late spring and early summer and coincided with the initial infestation and increase of the virus vector, the sugarcane aphid (Melanaphis sacchari). Aphid infestations in the experimental fields during 2002 and 2003 ranged from 1.2 to 33.0 and 1.0 to 4.2 aphids per leaf, respectively. Final disease incidences of 2.9, 5.2, and 5.2% were recorded in three fields planted with virus-free seed-cane. Distribution of ScYLV infections and aphids evaluated with spatial autocorrelation analysis indicated that ScYLV and its aphid vector both exhibited a predominantly random spatial distribution, with occasional aggregation. The low incidence and rates of disease increase observed, despite the widespread occurrence of potential vectors, suggest that inoculum pressure remains low in Louisiana. Therefore, it may be possible to keep yellow leaf at low levels by planting virus-free seed-cane.

Plant Disease ◽  
2000 ◽  
Vol 84 (10) ◽  
pp. 1085-1088 ◽  
Author(s):  
S. Schenck ◽  
A. T. Lehrer

Sugarcane, Saccharum spp. hybrid, is widely infected in the United States and many other countries with a yellowing and stunting disease called sugarcane yellow leaf syndrome. The causal agent, Sugarcane yellow leaf virus (ScYLV), is a Polerovirus of the Luteoviridae family. In this study, it was transmitted by the sugarcane aphid, Melanaphis sacchari, and also by the corn leaf aphid, Rhopalosiphum maidis, and the rice root aphid, R. rufiabdominalis. Two other aphids that infest sugarcane in Hawaii did not transmit the virus. Some Hawaiian sugarcane cultivars are susceptible to ScYLV, while others remain virus-free in the field. The latter were not infected when inoculated with viruliferous M. sacchari. Virus-free plants of susceptible cultivars were produced through apical meristem culture and were readily reinfected by viruliferous M. sacchari. They were also quickly reinfected when planted in a field in proximity to other infected sugarcane naturally infested with M. sacchari. Sugarcane cultivars are hybrids of several Saccharum species. In a field-grown collection of Saccharum and related species, 11 to 71% of the clones of four of the species were infected with ScYLV. None of the related genus Erianthus plants were infected, but four clones were infected experimentally by aphid inoculation. A low to moderate percentage of corn, rice, and sorghum seedlings became infected when inoculated with ScYLV, but barley, oats, and wheat proved to be very susceptible. None of seven weeds common in sugarcane fields were infected with ScYLV.


Plant Disease ◽  
2014 ◽  
Vol 98 (7) ◽  
pp. 1016-1016 ◽  
Author(s):  
M. Bouallegue ◽  
M. Mezghani-Khemakhem ◽  
H. Makni ◽  
M. Makni

Sugarcane yellow leaf virus (ScYLV) causes severe leaf symptoms in sugarcane (Saccharum spp.). It is a single-stranded RNA virus assigned to the genus Polerovirus, family Luteoviridae (1). ScYLV is transmitted by two aphid species, Melanaphis sacchari and Rhopalosiphum maidis. Although barley (Hordeum vulgare), oats (Avena sativa), and wheat (Triticum spp.) are susceptible to ScYLV when experimentally inoculated (3), this virus, related serologically to Barley yellow dwarf virus (BYDV)-RPV (4), has never been detected naturally in these cereals. In this study, 240 barley leaves were randomly collected from six fields in Tunisia following a north-south trend during the high infestation periods (March/April) in the 2013 growing season. Samples were tested by DAS-ELISA, using three antibodies (Bioreba AG, Switzerland), two of them, BYDV-B and BYDV-F, specific to luteoviruses corresponding to BYDV-PAV and BYDV-MAV, respectively, and the third one, BYDV-RPV, specific to the polerovirus synonymous to Cereal yellow dwarf virus (CYDV)-RPV. Based on DAS-ELISA, 30 samples were found positive for B/CYDV infection; 17 out of the 30 infected samples contained a single serotype, BYDV-PAV, and 13 out of the 30 infected samples contained two serotypes, PAV and RPV. Total RNA was extracted from all positive samples, and RT-PCR of the viral CP gene was performed with Lu1/Lu4 primers (2). A product of 531 bp was cloned and sequenced. The identities among the sequences determined varied between 80 to 100%, and from the 17 samples containing BYDV-PAV, six distinct BYDV-PAV sequences were revealed and named PAV-TN1 to PAV-TN6 (GenBank Accession No. JX402453 to JX402457 and KF271792). Fortuitously, all 13 positive samples corresponding to the serotypes PAV-RPV exhibited 98.7 to 99.3% identity with ScYLV isolates. These 13 samples contained three distinct sequences that were named ScYLV-Tun1 to ScYLV-Tun3 (GenBank Accession No. KF836888 to KF836890). Of the 17 PAV-positive samples collected, six were infected with PAV-TN1, four with PAV-TN2, four with PAV-TN3, one with PAV-TN4, one with PAV-TN5, and the last one with PAV-TN6. Of the 13 ScYLV-positive samples, seven were infected with ScYLV-Tun1, four with ScYLV-Tun2, and two with ScYLV-Tun3. Phylogenetic analysis showed that PAV-TN sequences formed a very tight cluster (>98%) corresponding to BYDV subspecies PAV-II, whereas all three Tunisian ScYLV sequences were clustered together. This study provides the first report of ScYLV isolates infecting barley crops in Tunisia, and confirms serological cross-reactivity between ScYLV and BYDV-RPV when commercial antibodies against BYDV-RPV are used. References: (1) C. J. D'Arcy and L. L. Domier. Page 891 in: Virus Taxonomy, 8th Report of the ICTV. C. M. Fauquet et al., eds. Springer-Verlag, New York, 2005. (2) N. L. Robertson and R. French. J. Gen. Virol. 72:1473, 1991. (3) S. Schenck and A. T. Lehrer. Plant Dis. 84:1085, 2000. (4) J. Vega et al. Plant Dis. 81:21, 1997.


Plant Disease ◽  
2007 ◽  
Vol 91 (3) ◽  
pp. 253-259 ◽  
Author(s):  
Youssef Abu Ahmad ◽  
Laurent Costet ◽  
Jean-Heinrich Daugrois ◽  
Samuel Nibouche ◽  
Philippe Letourmy ◽  
...  

Two experiments, one in Guadeloupe and one in Réunion Island, were performed to transmit different genotypes of Sugarcane yellow leaf virus (SCYLV) to eight sugarcane cultivars differing in resistance to infection by the virus and to yellow leaf. Transmission was attempted from SCYLV-infected sugarcane plants or leaves to healthy tissue-cultured plantlets grown in vitro and with the aphid vector Melanaphis sacchari. After inoculation and elimination of insects with an insecticide, plantlets were transferred to Montpellier, France and grown in a greenhouse. Plants were tested for presence of SCYLV by tissue-blot immunoassay and reverse-transcription polymerase chain reaction after 5 to 6 months of growth. SCYLV genotypes BRA-PER, CUB, and REU were detected in 47, 62, and 39% of plants inoculated with these genotypes in Guadeloupe, respectively. SCYLV genotypes BRA-PER and REU and a mixed infection of genotypes BRA-PER and REU were detected in 56, 33, and 42% of plants inoculated with these genotypes in Réunion Island, respectively. Genotypes BRA-PER and CUB could be transmitted to all eight sugarcane cultivars, but genotype REU could never be transmitted to resistant sugarcane cvs. H78-4153 and H78-3567. SCYLV genotype REU was transmitted successfully to sugarcane cv. R570 in Guadeloupe, but not in Réunion Island. Genotypes BRA-PER and CUB induced yellow leaf symptoms in susceptible or highly susceptible sugarcane cultivars, whereas genotype REU induced very few symptoms. SCYLV was not found in several symptomatic plants, suggesting an association of disease with undetectable populations of the virus or a nonviral cause. This is the first report of variation in infection capacity and in virulence of SCYLV.


Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 74-74 ◽  
Author(s):  
J. C. Comstock ◽  
M. Pena ◽  
J. Vega ◽  
A. Fors ◽  
B. E. L. Lockhart

In 1998, sugarcane plants with symptoms similar to yellow leaf syndrome were observed in Ecuador, Guatemala, and Nicaragua. These plants showed yellowing of the central portion of the third to sixth leaves on the abaxial surface from the youngest expanding spindle leaf. Intense yellowing and necrosis of the leaf tip and the central portion of the leaf blade near the midrib occurred in severe cases. A tissue blot immunoassay was used to detect Sugarcane yellow leaf virus (SCYLV) in the midrib of the top visible dewlap leaf (2) using an antiserum specific to a Florida isolate of SCYLV (1). Since the virus can be detected in asymptomatic plants, leaf samples were collected from both symptomatic and asymptomatic plants. Symptom expression was most intense in plants at maturity that were under stress. Cut ends of leaf samples were imprinted on nitrocellulose membranes in the country of origin, and control samples of healthy and SCYLV-infected leaves were imprinted in Florida on each membrane prior to serological processing. The results from the following locations and cultivars, and the ratio of SCYLV-positive samples over the total samples is indicated: Milagro, Ecuador, PR 70-2085 (11/24) and PR 76-3385 (48/63) in 1999; Escuintla, Guatemala, CP 57-603 (1/10), CP 73-1547 (0/10), CP 72-2086 (120/308), PR 75-2002 (8/11), PR 78-294 (10/10), and PR 87-2080 (13/13) in both 2000 and 2001; Tipitapa, Nicaragua, L 68-40 (21/70) in 1998; and Chinandega, Nicaragua, CP 72-2086 (30/30) and CP 74-2005 (13/45) in 2000. CP 72-2086 is a major commercial cultivar in Central American countries and was infected in both Guatemala and Nicaragua. SCYLV was detected in 9 of 10 cultivars sampled. An exception was noticed in CP 73-1547 in Guatemala where none of the 10 plants tested were infected; however this cultivar has a high incidence of SCYLV in Florida. Only 1 of 10 samples of CP 57-603 was SCYLV positive in Guatemala; however, this cultivar has a low incidence of infection in Florida and is considered more resistant than the other CP cultivars sampled. To our knowledge, this is the first report SCYLV in Ecuador, Guatemala, and Nicaragua. References: (1) S. M. Scagliusi and B. E. L. Lockhart. Phytopathology 90:120, 2000. (2) S. Schenck et al. Sugar Cane 4:5, 1997.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2122
Author(s):  
Luiz Eduardo Tilhaqui Bertasello ◽  
Michele Carmo-Sousa ◽  
Nathalie K. Prado Maluta ◽  
Luciana Rossini Pinto ◽  
João R. Spotti Lopes ◽  
...  

Sugarcane yellow leaf virus (ScYLV), Polerovirus, Luteoviridae, is one of the main viruses that infect sugarcane worldwide. The virus is transmitted by the aphid Melanaphis sacchari in a persistent, circulative manner. To better understand the interactions between ScYLV, sugarcane genotypes and M. sacchari, we explored the effect of sugarcane cultivars on the feeding behavior and biological performance of the vector. The number of nymphs, adults, winged, total number of aphids and dead aphids was assayed, and an electrical penetration graph (EPG) was used to monitor the stylet activities. Multivariate analysis showed changes in the vector’s behavior and biology on cultivars, identifying specific groups of resistance. In the cultivar 7569, only 5.5% of the insects were able to stay longer on sustained phloem ingestion, while in the other seven cultivars these values varied from 20% to 60%. M. sacchari showed low phloem activities in cultivars 7569 and Bio266. Overall, cultivar 7569 showed the worst biological performance of aphids, with the insects presenting mechanical difficulties for feeding and a shorter duration of the phloem period, and thus being considered the most resistant. We conclude that ScYLV virus infection in different sugarcane cultivars induced specific changes in the host plant, modifying the behavior of its main vector, which may favor or impair virus transmission.


The Holocene ◽  
2021 ◽  
pp. 095968362110259
Author(s):  
Anna Masseroli ◽  
Giovanni Leonelli ◽  
Umberto Morra di Cella ◽  
Eric P Verrecchia ◽  
David Sebag ◽  
...  

Both biotic and abiotic components, characterizing the mountain treeline ecotone, respond differently to climate variations. This study aims at reconstructing climate-driven changes by analyzing soil evolution in the late Holocene and by assessing the climatic trends for the last centuries and years in a key high-altitude climatic treeline (2515 m a.s.l.) on the SW slope of the Becca di Viou mountain (Aosta Valley Region, Italy). This approach is based on soil science and dendrochronological techniques, together with daily air/soil temperature monitoring of four recent growing seasons. Direct measurements show that the ongoing soil temperatures during the growing season, at the treeline and above, are higher than the predicted reference values for the Alpine treeline. Thus, they do not represent a limiting factor for tree establishment and growth, including at the highest altitudes of the potential treeline (2625 m a.s.l.). Dendrochronological evidences show a marked sensitivity of tree-ring growth to early-summer temperatures. During the recent 10-year period 2006–2015, trees at around 2300 m a.s.l. have grown at a rate that is approximately 1.9 times higher than during the 10-year period 1810–1819, one of the coolest periods of the Little Ice Age. On the other hand, soils show only an incipient response to the ongoing climate warming, likely because of its resilience regarding the changeable environmental conditions and the different factors influencing the soil development. The rising air temperature, and the consequent treeline upward shift, could be the cause of a shift from Regosol to soil with more marked Umbric characteristics, but only for soil profiles located on the N facing slopes. Overall, the results of this integrated approach permitted a quantification of the different responses in abiotic and biotic components through time, emphasizing the influence of local station conditions in responding to the past and ongoing climate change.


2021 ◽  
Vol 22 (13) ◽  
pp. 7129
Author(s):  
Desalegn D. Serba ◽  
Xiaoxi Meng ◽  
James Schnable ◽  
Elfadil Bashir ◽  
J. P. Michaud ◽  
...  

The sugarcane aphid, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae) (SCA), has become a major pest of grain sorghum since its appearance in the USA. Several grain sorghum parental lines are moderately resistant to the SCA. However, the molecular and genetic mechanisms underlying this resistance are poorly understood, which has constrained breeding for improved resistance. RNA-Seq was used to conduct transcriptomics analysis on a moderately resistant genotype (TAM428) and a susceptible genotype (Tx2737) to elucidate the molecular mechanisms underlying resistance. Differential expression analysis revealed differences in transcriptomic profile between the two genotypes at multiple time points after infestation by SCA. Six gene clusters had differential expression during SCA infestation. Gene ontology enrichment and cluster analysis of genes differentially expressed after SCA infestation revealed consistent upregulation of genes controlling protein and lipid binding, cellular catabolic processes, transcription initiation, and autophagy in the resistant genotype. Genes regulating responses to external stimuli and stress, cell communication, and transferase activities, were all upregulated in later stages of infestation. On the other hand, expression of genes controlling cell cycle and nuclear division were reduced after SCA infestation in the resistant genotype. These results indicate that different classes of genes, including stress response genes and transcription factors, are responsible for countering the physiological effects of SCA infestation in resistant sorghum plants.


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