A Topology-Based Stereo Matching Method for One Shot 3D Measurement Using Coded Spot-Array Structured Light

In this paper, a topology-based stereo matching method for 3D measurement using a single pattern of coded spot-array structured light is proposed. The pattern of spot array is designed with a central reference ring spot, and each spot in the pattern can be uniquely coded with the row and column indexes according to the predefined topological search path. A method using rectangle templates to find the encoded spots in the captured images is proposed in the case where coding spots are missing, and an interpolation method is also proposed for rebuilding the missing spots. Experimental results demonstrate that the proposed technique could exactly and uniquely decode each spot and establish the stereo matching relation successfully, which can be used to obtain three-dimensional (3D) reconstruction with a single-shot method.

First report of papaya ring spot virus (PRSV) infecting jute (Corchorus olitorius) in India

Jute is the most important bast fibre crop of the world, which is mainly cultivated in India, Nepal, Bangladesh, China, Indonesia and South American countries. The fibre is utilized for making apparels, ropes, bags, carpets etc (Biswas et al. 2014). This bio-fibre is gaining importance due to growing environmental consciousness worldwide. In June 2019, we noticed jute plants (less than 2%) showing virus like symptoms viz., downward curling, puckering, angular brownish to yellowish spots etc in a farmer’s field at Amdanga Block, North 24 Paraganas, West Bengal, India. To identify the virus, five symptomatic leaves from five different plants were used for high throughput sequencing (HTS). We extracted total RNA from each leaf which was subjected to construction of cDNA libraries. Sequencing was done on Illumina Hiseq 4000 (CytoScan, Thermo Fisher). Approximately 46 million 105 nt paired end reads were generated. Raw reads were trimmed and filtered to perform de novo assembly as described previously by (Grabherr et al. 2013). The obtained contig was 10,326 bp nucleotides (nt) long and in BLASTn against GenBank showed highest identity with papaya ring spot virus (PRSV) with the contig covering 99.6% of the viral genome. The obtained contig shared 99.33% sequence similarity with PRSV strain P (Accession No. MT470188). The selected leaf samples were also tested by double-antibody sandwich (DAS)- enzyme linked immunosorbent assay (ELISA) for papaya ring spot virus (PRSV) along with some common viruses, viz., Potato leaf roll virus (PLRV), Watermelon mosaic virus, Cowpea mosaic virus and Cucumber mosaic virus with the help of commercial diagnostic kits (Agdia). However, only the test with PRSV gave positive reaction for the symptomatic samples. The major symptoms of PRSV on papaya are severe mosaic, chlorosis, reduced lamina with curling and puckering (Gonsalves et al. 2010). To confirm PRSV infection, five symptomatic leaf samples (used for HTS) were collected and whole RNA was extracted from the samples using RNeasy plant minikit (Qiagen, USA). Reverse transcriptase polymerase chain reaction (RT-PCR) was conducted by using isolated RNA. One pair of PRSV specific primer (PSRV1F: 5' TTAAATCTGATTCGTC 3' PRSV 1R: 5'GAAATTCACGCAAAGTCGA3') was developed by using primer BLAST software and was used in RT-PCR assays. Amplified fragments were cloned and sequenced and all the fragments shared 98% sequence identity with PRSV. One of the amplicons was deposited in NCBI (Accession No. MN615832). Crude sap was prepared by homogenizing PRSV-infected jute leaf tissues in 0.1 M sodium phosphate buffer and 2% carborundum dust was added as abrasive (Holkar et al. 2018). The sap was then gently rubbed on to the healthy papaya leaves for inoculation. Typical PRSV like symptoms appeared in inoculated leaves 10 days post inoculation which confirmed the presence of PRSV-P. PRSV was detected by RT-PCR as well as (DAS)-ELISA from all inoculated infected papaya leaf tissues, but could not be detected from uninoculated healthy papaya tissues. To the best of our knowledge, this is the first report of PRSV-P infecting jute in India. References: Biswas, C. et al. 2014. Plant Dis. 98(4): 565. https:// doi.org/10.1094/PDIS-08-13-0826-PDN. Gonsalves, D. et al. 2010. The Plant Health Instructor. https:// doi.org/10.1094/PHI-I-2010-1004-01 Holkar, S. K. et al. 2018. Crop Protection. 108:110-119. https://doi.org/10.1016/j.cropro.2017.12.013 Grabherr, M. et al. 2011. Nat Biotechnol. 29(7): 644-652.

Influence of Bioregulators on Latex Yield and Proteolytic Activity of Papain Extracted from Field-grown TNAU Papaya CO. 8 under the Natural Incidence of Papaya Ring Spot Virus

The cultivation of papaya for both fruits and commercial papain extraction drastically suffers often due to the devastating incidence of papaya ringspot virus disease. The present study aimed to find out whether the papain yield and quality are influenced when bioregulators are applied to manage papaya ring spot virus (PRSV) incidence or as a measure to limit the height of the crop in TNAU Papaya CO.8 variety grown in the open field with the natural incidence of PRSV. Three growth retardants [250 ppm of prohexadione calcium (G2), 500 ppm of mepiquat chloride (G3) and 500 ppm of chlormequat chloride (G4)] and three stress tolerance promoting bioregulators [100 ppm of methyl jasmonate (S2), 100 ppm of salicylic acid (S3) and 0.6 g/ l of strobilurins (S4)] were employed in the study. Water spray (G1 and S1) was kept as control. The treatments were imposed at 4th and 8th months after planting. The growth retardants were initially sprayed and, in the subsequentweek ,the stress tolerance promoting bioregulators were sprayed as per the recommended doses. Among the combinations tried, spraying 250 ppm of prohexadione calcium followed by water spray (G2S1) a week later recorded the lowest plant height (140.79 cm) at the time of fruiting. The treatment combination G 2S2 involving 250 ppm of prohexadione calcium and 100 ppm of methyl jasmonate registered a higher number of fruits (42.17). The combination of 250 ppm of prohexadione calcium along with 100 ppm of salicylic acid (G2S3) was found to be the most effective combination to manage PRSV without compromising papain production and to enhance the proteolytic activity significantly (44378.36 TU g-1) as compared to other combinations. The treatment combination of 500 ppm of mepiquat chloride and 100 ppm of salicylic acid (G3S3) favored higher dry latex yield apart from a significant reduction in PRSV symptoms. Both these treatment combinations (G2S3 and G 3S3) merit due consideration in PRSV management for commercial fruit and papain production in papaya

Development of a Full-Length Infectious cDNA Clone of the Grapevine Berry Inner Necrosis Virus

Grapevine berry inner necrosis virus (GINV) belongs to the genus Trichovirus in the family Betaflexiviridae. The GINV isolate LN_BETA_RS was obtained from a “Beta” grapevine (Vitis riparia × Vitis labrusca) exhibiting chlorotic mottling and ring spot in Xingcheng, Liaoning Province, China. To verify the correlation between GINV and grapevine chlorotic mottling and ring spot disease, we constructed an infectious cDNA clone of GINV isolate LN_BETA_RS using the seamless assembly approach. Applied treatments of agroinfiltration infectious cDNA confirmed systemic GINV infection of the Nicotianaoccidentalis 37B by reverse transcription polymerase chain reaction (RT-PCR) and transmission electron microscopy, exhibiting chlorotic mottling symptoms on leaves. Infectious cDNA was also transmitted to new healthy N. occidentalis plants through rub-inoculation. Moreover, the cDNA clone was agroinfiltrated into “Beta” and “Thompson Seedless” grapevine plantlets, and the inoculated grapevines exhibited leaf chlorotic mottling and ringspot during the two years of observation. GINV-inoculated “Beta” grapevines had serious leaf chlorotic mottling and ringspot symptoms on the whole plant, while relatively few symptoms were observed on the leaves of agroinoculated “Thompson Seedless” grapevines in early spring and only weak ring spot gradually appeared later in the top young leaves. Our experiments fulfilled Koch’s postulates and revealed the causative role of GINV in grapevine chlorotic mottling and ring spot disease.