20133A-- Jandrajupalli Sridhar Indian Journal of Entomology 83 (2021) Online published Ref. No. e20133A DoI No.: 10.5958/0974-8172.2020.00262.X OCCURRENCE OF AULACORTHUM SOLANI ON POTATO: A VECTOR OF POTATO VIRUS YO AND POTATO LEAFROLL VIRUS IN INDIA JANDRAJUPALLI SRIDHAR1*, VALLEPU VENKATESWARLU5, NEELAM KUMARI, ANUJ BHATNAGAR2, BASWARAJ R, RAVINDER KUMAR, M NAGESH3, JAGESH K TIWARI, AND S K CHAKRABARTI ICAR- Central Potato Research Institute (CPRI), Shimla 171001, Himachal Pradesh 1Present address: ICAR- National Institute of Biotic Stress Management, Baronda, Raipur 493225, Chhattisgarh 2ICAR- CPRI Centre, Modipuram, Meerut 250110, Uttar Pradesh 3ICAR- National Bureau of Agricultural Important Insect Resources, Post Bag No. 2491, H A Farm P O, Bellary Road, Bangalore 560024 5ICAR- Central Tobacco Research Institute, Bhaskarnagar, Rajahmundry 533105 Andhra Pradesh *Email: [email protected] (corresponding author) ABSTRACT Foxglove aphid Aulacorthum solani is a polyphagous pest causing direct and indirect losses to crops, and potato is its important host. Its incidence and distribution have extended manifolds in potato growing regions of India especially in seed production areas. In the recent past, it has been occurring on potato in the four agroecosystems of Shimla, Jalandhar, Modipuram and Gwalior. This study determines species distribution and its viruliferous nature with respect to most predominant viruses viz., Potato virus Yo (PVYo) and Potato leafroll virus (PLRV). Adults of A. solani (prestarved) were given an acquisition feeding of 24 hr on pure culture of PVYo and PLRV, and then released on to tissue culture raised healthy potato seedlings for inoculation. These plants were allowed for expression of external visual symptoms and were PCR tested at weekly intervals for 35 days. PCR results revealed that PVYo and PLRV were first detected in plants at 2nd week after inoculation but with no visible symptoms. However, clear visual symptoms of PVYo and PLRV were witnessed during 4th week after inoculation confirming viruliferous nature of A. solani. It was further confirmed by sequencing coat protein gene of two viruses and comparing with reported sequences in the database. Key words: Aulacorthum solani, PVYo, PLRV, vector, potato, acquisition feeding, viruliferous nature, detection, PCR, symptoms, coat protein, sequencing INTRODUCTION crops, A. solani is considered as polyphagous, and infests nearly every plant that is attacked by green peach Aulacorthum solani commonly known as foxglove aphid (Myzus persicae) or melon aphid (Aphis gossypii). aphid or glasshouse potato aphid is a polyphagous In India, A. solani has been reported on potato for the pest infesting > 95 plants belonging 25 families (Kim first time in Uttar Pradesh (Bhatnagar et al., 2017). It is a et al., 1991). It is native to Europe (Blackman and vector of 45 plant viruses globally (Miller and Stoetzel, Eastop, 2000), but now is a cosmopolitan including 1997). It is a serious vector of SbDV-YS and SbDV-DS India (Rebijith et al., 2013). In recent years, this strains in soybean. It is also a vector of Raspberry leaf aphid has become a major pest of many agricultural curl, Raspberry vein chlorosis, Bean leaf roll, Legume and greenhouse crops worldwide including potato yellows virus, Pea enation mosaic, Lettuce speckles, (Jaundricic et al., 2010). Although originally described Tobacco rosettee, Tobacco vein distorting, Beet western from potato (Solanum tuberosum) (Blackman and yellows, Beet mild yellow virus etc. (Sylvester, 1980). Eastop, 2000), Digitalis purpurea L. (common Recently, Zucchini yellow mosaic virus and Johnson foxglove) and Hieracium spp. (common perennial grass mosaic potyvirus in maize were found transmitted hawkweed) are its primary hosts in North America by A. solani (Marino et al., 2010). It had been reported (Wave et al., 1965). Damage due to its honey dew that A. solani transmit PVY (non-circulative virus) secretion, leaf discoloration and plant defoliation at high and PLRV (circulative virus). PLRV belonging to densities is known (Sanchez et al., 2007). In greenhouse Polerovirus (family: Luteoviridae) is one of the most 2 Indian Journal of Entomology 83 (2021) Online published Ref. No. e20133A important viruses having worldwide distribution of Kufri-Fagu and single gravid female was used to including India and is known to cause yield losses of up raise pure culture on potato and brinjal seedlings in to 60-75% (Raigond et al., 2019). As a vector in potato, insect proof cages (25± 2oC, 75± 5%RH). Culture was it has significant impact on seed potato production in maintained on potato and brinjal by shifting young India, and It has been observed to infest potato in the first instar nymphs on to fresh seedlings. Pure culture seed producing farms of CPRI during past three years. of PVYo and PLRV (tested and found positive prior to So far, the population dynamics of M. persicae and transmission studies) was obtained from virus culture A. gossypii were only taken into account for decision facility at CPRI, Shimla for conducting acquisition making for healthy potato seed production in India. study. Pure and healthy seedlings of potato cv. Kufri Therefore, it is imperative to generate authentic data Pukhraj and Kufri Surya (only for PVYo) obtained on viruliferous nature of A. solani with respect to the from Division of Seed Technology, CPRI, Shimla were most important viruses, PVYo and PLRV under Indian raised in potted plants. These seedlings were tested for conditions. This aphid may also contribute its part PVYo, PLRV and ToLCNDV-potato using coat protein in horizontal transmission of these viruses and cause specific primers in PCR prior to transmission studies yield loss in addition to Myzus persicae, Macrosiphum and virus free seedlings were selected for subsequent euphorbiae (Thomas) and Aphis gossypii (Sridhar et al., transmission studies. For acquisition, inoculation and 2020). Therefore, understanding its vectorial efficiency transmission study, two varieties in four replications is required as it might pose serious threat to healthy were used. A total of 50 healthy well grown A. solani potato seed production. were allowed on to pure culture of PVYo and PLRV for acquisition feeding of 24 hr. Preliminary study MATERIAL AND METHODS on acquisition of PVY confirmed acquisition of o Aulacarthum solani incidence was monitored PVY and PLRV after 24 hr. These apterous adults using yellow sticky traps and by manual roving were released on to healthy seedlings (30 days old, survey on potato at Kufri-Fagu, Jalandhar and 15 each) for an inoculation feeding period of 24 hr. Modipuram, Gwalior and Patna which are major Then, these were killed with imidacloprid (17.8SL potato seed production centres. It was observed as @ 0.03%) and seedlings were allowed and examined counts/ 100 compound leaves (Chandla et al., 2004), for expression of visual symptoms for a period of 5 with identification done using morphological (Joshi weeks and the experiment was repeated. The leaf et al., 2013; Remaudiere, and Remaudiere, 1997) and samples were collected at weekly intervals and total molecular markers. The total nucleic acid was extracted genomic RNA was isolated using RNA isolation kit from individual samples using print capture technique. (Sigma Aldrich). cDNA was synthesized using random PCR was performed for molecular identification primers with Revert Aid TM c-DNA synthesis kit as per the standard protocol (Sridhar et al., 2015). from Fermentas Life Sciences (Baswaraj et al., 2014). Polymerase chain reaction was carried out using coat Molecular identity was confirmed by sequencing o the mtCOI gene by amplifying and sequencing protein specific primers for PVY (Forward- PVY- FCP-5’-ACGTGGTATGAGGCAGTGCGGA-3’ and mitochondrial COI gene using forward primer, LCO- 1490- 5’-GGTCAACAAATCATAAAGATATTGG-3’ Reverse-5’-ATGTGCGCTTCCCTAGCCCTCA-3’) and reverse primer, HCO-2198 and for PLRV (Forward- PLRV-FCP-5’- 5’-TAAACTTCAGGGTGACCAAAAAATCA-3’ CTAACAGAGTTCAGCCAGTGGTTA- and compared with reference sequences in NCBI. 3’and reverse- PLRV-RCP-5’- The viruliferous nature was determined by extracting CGGTATCTGAAGATTTTCCATTTC-3’). Polymerase chain reaction was carried out using coat protein specific the nucleic acid from individual samples using print o capture technique (Sridhar et al., 2015; Raigond et al., primers for PVY and PLRV. PCR conditions were 2019). The field collected aphid samples were screened followed as per Baswaraj et al. (2014). The amplified for their viruliferous nature with respect to PVYo and products were resolved on 1.0% agarose gel, stained PLRV following the standard protocols (Sridhar et al., with ethidium bromide (10μg/ ml) and visualized in a 2015; Raigond et al., 2019; Venkateswarlu et al., 2016; gel documentation system. Baswaraj et al., 2014; Raigond et al., 2018). RESULTS AND DISCUSSION For culturing A. solani, viruses and test plants, Aphids were sampled from 30 locations representing samples of A. solani were collected from potato fields 17 states of India with major emphasis on the Indo- Occurrence of Aulacorthum solani on potato: A vector of Potato virus YO and Potato leafroll virus in India 3 Jandrajupalli Sridhar et al. Gangetic plains where seed production is being done. only found to be major vectors of potato viruses in Among the seed production centres of CPRI, A. solani India. Only recently, A. solani has been found to occur was recorded from Shimla, Jalandhar, Modipuram and on potato (Sridhar et al., 2015) Gwalior which was not