Potato Leaflets Research Articles

Effects of application methods of microbial mixture on early blight disease (Alternaria solani) and growth of potato

Early blight (Alternaria solani) is one of important diseases in potato in Indonesia. In previous study, a microbial consortium (Trichoderma harzianum, Bacillus subtilis and Pseudomonas sp.) suppressed the bacterial wilt disease in potato. For application, the microbial consortium was mixed with compost (10%). As the microbial consortium is originally intended for controlling soil-borne diseases, this study examined the ability of the microbial consortium to suppress early blight disease and the effects of application methods on its efficacy. The application methods examined were the methods that targeted for soil-borne as well as airborne diseases. The experiment was conducted in a greenhouse at the Department of Plants and Diseases, Faculty of Agriculture, Universitas Padjadjaran, Sumedang, West Java, Indonesia. The experiment used Randomized Complete Block Design with 10 treatments and three replications. The treatments included application of microbes mixed with compost in planting hole solely or in combination with soaking the potato tubers in suspension of the microbes, drenching water extract of the mixture at 2, 4, 6 weeks after planting (WAP) with or without foliar application of the water extract. The result showed that application method influenced the abilities of the microbial mixture in suppressing early blight disease and supporting the potato growth. Even though the application of microbe-compost in planting medium inhibited the development of early blight disease by 37.8-39.5%, the regular foliar spray of the water extract of the mixture enhanced the disease suppression. Combination between application of the microbe-compost in the planting hole, drenching its water extract at 2, 4, 6 WAP and weekly foliar spray of the water extract suppressed early blight disease by 80.8%. This combination of application methods also supported better plant height, numbers of potato leaflets, roots fresh weight and production of potato tuber.

Phenotypic and Genotypic Analysis of the Population of Phytophthora infestans in Bangladesh Between 2014 and 2019

In Bangladesh, the third largest producer of potatoes in Asia, late blight, caused by Phytophthora infestans, is the major constraint to production. Nevertheless, there is a lack of published information on the pathogen population. A collection of 69 isolates obtained from samples of infected potato foliage collected in 2018–2019 varied significantly in their aggressiveness to detached potato leaflets and tuber slices of cv. Diamant. On leaflets, most isolates were highly aggressive, colonizing more than half the surface in 7 days. On tuber slices, while some isolates were highly aggressive, those collected in 2019 were less so. There was a significant effect of the locations from which the isolates were obtained on aggressiveness to both leaflets and tuber slices, but aggressiveness to leaflets and to tuber slices was not significantly correlated. All isolates were A2 mating type and either intermediate (38%) or resistant (62%) in sensitivity to the fungicide metalaxyl. A subset of 24 isolates all had mitochondrial DNA haplotype Ia.Samples of P. infestans DNA (124) from infected potato foliage obtained from Bangladesh (2014–2019) were genotyped by 12-plex SSR. The vast majority (95%) were assigned to EU_13_A2, which was present in every year in which samples were collected. Numerous EU_13_A2 variants were identified, many specific to Bangladesh. Six samples (from 2017 to 2019) had genotypes distinct from EU_13_A2 and with no close match to known European lineages. It is concluded that the current P. infestans population of Bangladesh is dominated by the aggressive lineage EU_13_A2, also dominant in India and Pakistan. The implications of this for control of late blight are discussed.

Characterization of Phytophthora infestans Isolates from Two Potato Varieties in the Highlands Agro-Ecological Zone of Cameroon

Background: Late blight caused by Oomycete Phytophthora infestans remains a huge problem in potato production and one of the most severe crop diseases worldwide. In Cameroon, the populations characterization of this pathogen remain very little known.
 Aims: This study aims to characterize isolates of P. infestans collected in twelve localities of Highlands zone of Cameroon.
 Study Design: Twelve localities in three main potato production areas of the Highlands agro-ecological zone (HAZ) in Cameroon were selected for sample collection. The phenotypic parameters of sporangia were measured. The presence of mating types and pathogenicity tests on detached leaflets of two potato varieties (MANATE and CIPIRA) were assessed.
 Results: A total of 36 isolates were collected. Height (08) Sporangia shape of P. infestans were obtain and 02 new different shape were pip form and oval to ellipsoid. Sporangia length/width ratio ranged from 1.62 to 2.18. Mating types A1 and A2 were present in the studied areas. Pathogenicity test on detached potato leaflets was positive with all the 36 isolates. The isolate HPBT02 from Tsela locality was more aggressive (P<0.05). MANATE variety was more susceptible.
 Conclusion: The study shows that mating types A1 and A2 of P. infestans exit in Cameroon and the morphology of sporangia varies according to the localities. Molecular characterization is needed.

The ability of the green peach aphid (Myzus persicae) to penetrate mesh crop covers used to protect potato crops against tomato potato psyllid (Bactericera cockerelli).

In Central and North America, Australia and New Zealand, potato (Solanum tuberosum) crops are attacked by Bactericera cockerelli, the tomato potato psyllid (TPP). ‘Mesh crop covers’ which are used in Europe and Israel to protect crops from insect pests, have been used experimentally in New Zealand for TPP control. While the covers have been effective for TPP management, the green peach aphid (GPA, Myzus persicae) has been found in large numbers under the mesh crop covers. This study investigated the ability of the GPA to penetrate different mesh hole sizes. Experiments using four sizes (0.15 × 0.15, 0.15 × 0.35, 0.3 × 0.3 and 0.6 × 0.6 mm) were carried out under laboratory conditions to investigate: (i) which mesh hole size provided the most effective barrier to GPA; (ii) which morph of adult aphids (apterous or alate) and/or their progeny could breach the mesh crop cover; (iii) would leaves touching the underside of the cover, as opposed to having a gap between leaf and the mesh, increase the number of aphids breaching the mesh; and (iv) could adults feed on leaves touching the cover by putting only their heads and/or stylets through it? No adult aphids, either alate or apterous, penetrated the mesh crop cover; only nymphs did this, the majority being the progeny of alate adults. Nymphs of the smaller alatae aphids penetrated the three coarsest mesh sizes; nymphs of the larger apterae penetrated the two coarsest sizes, but no nymphs penetrated the smallest mesh size. There was no statistical difference in the number of aphids breaching the mesh crop cover when the leaflets touched its underside compared to when there was a gap between leaf and mesh crop cover. Adults did not feed through the mesh crop cover, though they may have been able to sense the potato leaflet using visual and/or olfactory cues and produce nymphs as a result. As these covers are highly effective for managing TPP on field potatoes, modifications of this protocol are required to make it effective against aphids as well as TPP.

Downregulation of imidacloprid resistant genes alters the biological parameters in Colorado potato beetle, Leptinotarsa decemlineata Say (chrysomelidae: Coleoptera)

Colorado potato beetle, Leptinotarsa decemlineata Say (coleoptera: chrysomelidae), is the important pest of potato all over the world. This insect pest is resistant to more than 50 active compounds belonging to various chemical groups. Potential of RNA interference (RNAi) was explored to knock down transcript levels of imidacloprid resistant genes in Colorado potato beetle (CPB) under laboratory conditions. Three important genes belonging to cuticular protein (CP), cytochrome P450 monoxygenases (P450) and glutathione synthetase (GSS) families encoding imidacloprid resistance were targeted. Feeding bio-assays were conducted on various stages of imidacloprid resistant CPB lab population by applying HT115 expressing dsRNA on potato leaflets. Survival rate of insects exposed to CP-dsRNA decreased to 4.23%, 15.32% and 47.35% in 2nd, 3rd and 4th instar larvae respectively. Larval weight and pre-adult duration were also affected due to dsRNAs feeding. Synergism of RNAi with imidacloprid conducted on the 2nd instar larvae, exhibited 100% mortality of larvae when subjected to reduced doses of GSS and CP dsRNAs along with imidacloprid. Utilization of three different dsRNAs against imidacloprid resistant CPB population reveal that dsRNAs targeting CP, P450 and GSS enzymes could be useful tool in management of imidacloprid resistant CPB populations.

Long term field sampling in Sweden reveals a shift in occurrence of cytochrome b genotype and amino acid substitution F129L in Alternaria solani, together with a high incidence of the G143A substitution in Alternaria alternata

The incidence of the pathogenic fungus Alternaria solani on potato during the years 2009 to 2016 was analysed and the distribution of the two genotypes of cytochrome b (genotype 1, GI and genotype 2, GII) determined. Potato leaflets with lesions resembling early blight were collected in August and September 2009–2016 in the south-eastern part of Sweden and during 2010 and 2012–2014 in the central part of Sweden. In total, 2042 potato leaflet samples were analysed using diagnostic PCR methods. Alternaria solani was more commonly found in the samples collected later in the growing seasons. The occurrence of substitutions in the gene encoding cytochrome b, associated with loss of sensitivity towards strobilurins, was determined by sequencing a segment in the target gene in all confirmed A. solani samples. The proportion of A. solani GI decreased in relation to GII over the years. All except five GI samples were non-mutated. Genotype 2 was already present in the first year of sampling but only one sample possessed the F129 L substitution. A distinct shift from non-mutated GII to GII F129 L was observed between the season of 2011–2012 and a similar shift occurred in the pathogen population from GI to GII between 2012 and 2013. Identification of Alternaria alternata was performed during 2009–2013. The species was most often in co-occurrence with A. solani. Most of the samples investigated possessed the G143A substitution associated with strobilurin resistance.

REACTION OF POTATO CULTIVARS AND CLONES TO Phytophthora infestans

ABSTRACT The in vitro and field reactions of 23 potato cultivars and clones to two isolates of Phytophthora infestans were tested. The in vitro test used the detached potato leaflets method, and disease severity was evaluated 6 days after inoculation. Field experiments were conducted in autumn of 2013, in two locations in Pelotas City, Rio Grande do Sul State, Brazil. Seven evaluations of the disease severity were performed. From the severity values, the area under the disease progress curve (AUDPC) was calculated. Tubers were harvested to determine the yield (g plot-1). The A2 mating type isolate was the most aggressive for the majority of the potato genotypes. It was possible to group the different reactions of the potato genotypes based on the AUDPC values. Clones C2553-1-06, C2573-4-06, C2550-4-06, C2551-2-06, and CIP392,617.54 showed moderate-to-high resistance to the two isolates of P. infestans. The values of severity and AUDPC obtained in vitro and field tests were positively correlated for both P. infestans isolates, but in some interactions, inconsistencies were observed. Tuber yield was negatively correlated with AUDPC.

Impact of long-lasting insecticide-incorporated screens onColorado potato beetle and plum curculio

The efficacy and behavior effects of long-lasting insecticide-incorporated screens (LLIS; polyolefin containing deltamethrin) were tested under laboratory conditions against two important pests ( Leptinotarsa decemlineata and Conotrachelus nenuphar ). Four Vestergaard ZeroFly® LLISs of different specifications were evaluated: trial batches JLCB061009, SPSA 6616, ZeroFly Greenhouse (B), and ZeroFly Greenhouse (G). Two control products were also included: ZeroFly Screen Greenhouse White with no insecticide and a standard commercial fiberglass insect screen. Contact bioassays revealed that all treated LLIS products, except JLCB061009, provided >90% mortality within 24 h of exposure for both susceptible (New Jersey, USA) and resistant (Long Island, NY, USA) L. decemlineata colonies. The LT 50 values for the LLISs ranged from 30 to 51 min. Behavioral tests revealed that L. decemlineata adults were unable to feed on potato leaflets in all treatments except in the case of JLCB061009. In the contact bioassays conducted on C. nenuphar , the maximum mortality (98%) was observed with ZeroFly Greenhouse (B). There was no feeding scar on any apples in all treatments except JLCB061009. LLISs provided a high level of protection against Colorado potato beetle and plum curculio under laboratory conditions. Further studies with different species and under field conditions are needed to determine the full potential of LLISs for agricultural pest management.

Phytophthora infestans Effectors IPI-O1 and IPI-O4 Each Contribute to Pathogen Virulence.

Potato late blight, caused by the oomycete pathogen Phytophthora infestans, is one of the most destructive plant diseases. Despite decades of intensive breeding efforts, it remains a threat to potato production worldwide, because newly evolved pathogen strains have overcome major resistance genes quickly. The RB protein, from the diploid wild potato species Solanum bulbocastanum, confers partial resistance to most P. infestans strains through its recognition of members of the corresponding pathogen effector protein family IPI-O. IPI-O comprises a multigene family and while some variants are recognized by RB to elicit host resistance (e.g., IPI-O1 and IPI-O2), others are able to elude detection (e.g., IPI-O4). IPI-O1 is almost ubiquitous in global P. infestans strains while IPI-O4 is more rare. No direct experimental evidence has been shown to demonstrate the effect of IPI-O on pathogen virulence in the P. infestans-potato pathosystem. Here, our work has demonstrated that in planta expression of both IPI-O1 and IPI-O4 increases P. infestans aggressiveness resulting in enlarged lesions in potato leaflets. We have previously shown that IPI-O4 has gained the ability to suppress the hypersensitive response induced by IPI-O1 in the presence of RB. In this study, our work has shown that this gain-of-function of IPI-O4 does not compromise its virulence effect, as IPI-O4 overexpression results in larger lesions than IPI-O1. We have also found that higher expression of IPI-O effectors correlates with enlarged lesions, indicating that IPI-O can contribute to virulence quantitatively. In summary, this study has provided accurate and valuable information on IPI-O's virulence effect on the potato host.

Isolation of Apoplast.

The apoplast can be described as the soluble fraction of the extracellular space of plant tissue, and it plays an important role in signaling, nutrient transport, and plant-pathogen interactions. In this protocol, we describe a method where leaves are infiltrated with phosphate buffer under vacuum. The apoplast can then be extracted by centrifugation and simultaneously collected in a protease inhibitor solution. Using this protocol, typically 3 μg of apoplastic proteins can be obtained in a volume of 300 μL from five potato leaflets, with minimal contamination by non-apoplastic proteins.

Is Discrimination of 13C in Potato Leaflets and Tubers an Appropriate Trait to Describe Genotype Responses to Restrictive and Well‐Watered Conditions?

AbstractSelection for drought tolerance entails prioritizing plant traits that integrate critical physiological processes occurring during crop growth. Discrimination against 13C (∆) in leaflets (∆leaflet) and tubers (∆tuber) was compared under two water regimes in two potato‐improved varieties selected to maintain yield under drought conditions (Unica and Sarnav) and one drought susceptible European cultivar (Désirée). In the control treatment, soil water content was kept at field capacity over the whole growth cycle, while in the drought treatment water supply was restricted after tuber initiation (50 % of field capacity). Gas exchange and N content per unit leaf area (Narea) as well as ∆ were assessed at different stages. Sarnav showed the highest tuber yield in both water conditions, suggesting that yield in the water restriction treatment was largely driven by yield potential in this genotype. Higher stomatal conductance (gs) and Narea and lower ∆leaflet in well‐watered Sarnav suggested higher photosynthetic capacity. Under water restriction, Sarnav maintained higher gs indicating that carbon diffusion was a key factor for biomass accumulation under water restriction. Our results suggest the use of ∆ determined after tuber initiation as an indirect selection indicator for tuber yield under both well‐watered and restricted soil water availability conditions.

Combined effects of CO2 enrichment, diurnal light levels and water stress on foliar metabolites of potato plants grown in naturally sunlit controlled environment chambers.

Experiments were conducted in outdoor, naturally sunlit, soil-plant-atmosphere research (SPAR) chambers using plants grown in pots. Drought treatments were imposed on potato plants (Solanum tuberosum cv. Kennebec) beginning 10 days after tuber initiation. A total of 23 out of 37 foliar metabolites were affected by drought when measured 11 days after initiating water stress treatments. Compounds that accumulated in response to drought were hexoses, polyols, branched chain amino acids (BCAAs) and aromatic amino acids, such as proline. Conversely, leaf starch, alanine, aspartate and several organic acids involved in respiratory metabolism decreased with drought. Depending upon harvest date, a maximum of 12 and 17 foliar metabolites also responded to either CO2 enrichment or diurnal treatments, respectively. In addition, about 20% of the measured metabolites in potato leaflets were simultaneously affected by drought, CO2 enrichment and diurnal factors combined. This group contained BCAAs, hexoses, leaf starch and malate. Polyols and proline accumulated in response to water stress but did not vary diurnally. Water stress also amplified diurnal variations of hexoses and starch in comparison to control samples. Consequently, specific drought responsive metabolites in potato leaflets were dramatically affected by daily changes of photosynthetic carbon metabolism.

Host–pathogen interaction between Phytophthora infestans and Solanum tuberosum following exposure to short and long daylight hours

The influence of short and long day length on the expression of qualitative and quantitative resistance to Phytophthora infestans in potato was studied. The incompatible interaction was tested for available set of isolates avirulent in greenhouse conditions to potato Black’s differentials possessing the genes: R2, R5, R6, R8, R9, R10, and standard potato cultivar Tarpan (no known R gene). The avirulent isolates either were completely avirulent regardless of plant growing conditions, or they infected leaflets of these differentials more frequently when plants were exposed previously to short day conditions than to long day conditions. This study highlights the importance of day length, among many other factors which are controlled, in testing the expression of the virulence of P. infestans isolates. In compatible interactions, when quantitative resistance was evaluated in differentials with gene R1, R3, R4, R7, R11, and potato cultivar Craigs Royal (no known R gene), stronger infection expressed by lesion growth rate, as well as stronger sporulation, were observed on potato leaflets of plants exposed to short day for 6–7 weeks before inoculation. The analysis of variance revealed a significant contribution to variation in lesion growth rate of day length, genotype, as well as day length by genotype interaction. Significant influence of isolate, and genotype, but not day length, on the expression of the incubation period was found. The results indicate the necessity of evaluating components of partial resistance present in potato lines used in breeding potato resistant to P. infestans in destined day length growing conditions.

Species specific primers for identification of Alternaria solani, in combination with analysis of the F129L substitution associates with loss of sensitivity toward strobilurins

A species specific forward primer was designed in order to identify the phytopathogenic fungus Alternaria solani, which causes early blight on potato. The reverse primer came from another survey of the American population of A. solani. The combination of these two primers can be used both as molecular identification of A. solani as well as sending the PCR product for sequencing in search for the F129L substitution associated with loss of sensitivity toward fungicides based on strobilurins. The diagnostic method has been successfully used when identifying the causal agent of lesions on potato leaflets during large field assays.

‘New species association’ biological control? Two coccinellid species and an invasive psyllid pest in New Zealand

The ‘new species association’ biological control approach is based on the ecological principle in which a natural enemy is used that has not coevolved with a pest. The recent incursion of the tomato–potato psyllid (TPP), Bactericera cockerelli to New Zealand offered a unique opportunity to investigate the potential of a new species association for biological control of this pest. This laboratory-based study investigated the potential for a new species association between two New Zealand naturalized coccinellids, Cryptolaemus montrouzieri and Cleobora mellyi, and TPP. A third naturalized New Zealand coccinellid, Scymnus loewii, was compared as a potential ‘old association’. We conducted two experiments to determine consumption rate and feeding behavior, respectively, of adults and fourth-instar larvae of the three coccinellid species on mixed instars of TPP nymphs, using tomato and potato leaflets, and a no-leaflet control. C. montrouzieri consumed up to 30 psyllids over 24h, depending on leaflet type and predator life stage. C. mellyi adults and larvae were the most voracious predators of psyllids, consuming up to 100 TPP over 24h. Adult C. mellyi spent more time feeding on psyllids in the control (56%) and potato leaflets (30%) than on tomato leaflets. Larvae spent 79% more time feeding on the no-leaflet control, compared to the potato (24%) and tomato leaflet (14%) treatments. S. loewii consumed relatively few psyllids on all three substrates (<10 over 24h), and spent less time feeding compared to the other two species. By demonstrating that these predators will consume this psyllid, our results suggest that a new species association may potentially exist between C. montrouzieri, C. mellyi and the TPP.

Dose–response relationships for the antifeedant effects of Humulus lupulus extracts against larvae and adults of the Colorado potato beetle

Dose-response relationships for antifeedant effects of H. lupulus extracts against larvae and adults of the Colorado potato beetle (CPB) were determined in laboratory conditions. The larval and adult beetles were fed on potato leaflets treated with H. lupulus extract ranging from 0.4 to 40 mg mL(-1) in a no-choice situation. Their feeding behavior was recorded, and larval growth and antifeedant indexes were calculated. H. lupulus treatments significantly affected larval growth rate, and at higher concentrations the larval weights were significantly reduced over the course of the assay. Adults of CPB were more sensitive to the extracts than the larvae, and, even at lower doses, adult beetles were arrested for longer periods than larvae. These results indicate that H. lupulus extracts may have potential for control of CPB, particularly in organic farms where conventional insecticides are not available.

Probing Behavior of Apterous and Alate Morphs of two Potato—Colonizing Aphids

Secondary host plant colonization by aphids involves alate and apterous morphs to spread in the population at a large scale by flying or, at a finer one, by walking. Macrosiphum euphorbiae Thomas (Hemiptera: Aphididae) and Myzus persicae Sulzer (Hemiptera: Aphididae) are two polyphagous aphids that cause serious losses on many crops, particularly on potato, Solanum tuberosum L. (Solanales: Solanaceae). When settlement of virginoparous alate aphids occurs, apterous individuals are produced and spread within the potato field. As these two potato colonizers originate from different areas and show different body length, this study compared probing behaviors of virginoparous alate and apterous M. persicae and M. euphorbiae on one of their secondary host plants, Solanum tuberosum. Non—choice bioassays and electrical penetration graph (EPG) recordings were performed. Most M. euphorbiae of the two morphs rapidly accepted potato plants and exhibited long duration of probing, phloem sap salivation, and ingestion phases. In contrast, at the end of the experiment, most alates of M. persicae left the potato leaflet after brief gustative probes. Moreover, EPG experiments showed that the main difference between both morphs of the two species concerned the xylem ingestion parameter. Differences between species were also reported, such as an increased total duration of probing in both morphs and enhanced phloem ingestion duration in apterous M. euphorbiae. All the differences highlighted in this study are discussed according to the variations observed in aphid body size and to their historical association with Solanum species.

Grasshopper Injury to Potato: Consumption, Effect on Photosynthesis, and Economic Injury Level

Generalist grasshopper species feed at agricultural field edges, often triggering management practices because of defoliation injury. Few controlled studies in agroecosystems, however, have quantified grasshopper consumption or plant photosynthetic response to feeding. Consequently, we examined if injury caused by the red‐legged grasshopper Melanoplus femurrubrum (DeGeer), would influence the gas exchange parameters on the remaining tissue. We conducted this examination on three potato (Solanum tuberosum L.) cultivars (Norkotah, Atlantic, and Frito‐Lay proprietary) and at three times during potato growth (all post flowering). With injury rates of about 10 to 25%, we observed no significant change in photosynthetic rates on the remaining leaf tissue in any cultivar or in any of the three experiments. Additionally, we measured potato canopy area and, in the laboratory, placed individual M. femurrubrum on premeasured potato leaflets. Individual grasshoppers consumed a mean of 4.4 cm2 d−1 of leaf area. Early in the season when potato plant leaf area indices (LAIs) are less than about 4.5, grasshoppers have the potential to significantly reduce yield. When potato canopies reach LAIs of 5.0, however, which in Nebraska typically occurs in July when grasshopper numbers also increase, grasshopper densities are rarely high enough to justify treatment.

Behavioral responses of adult potato psyllid, Bactericera cockerelli (Hemiptera: Triozidae), to potato germplasm and transmission of Candidatus Liberibacter psyllaurous

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is a major pest of potatoes that can cause yield loss by direct feeding on crop plants and by transmitting a bacterial pathogen, Candidatus Liberibacter psyllaurous (a.k.a. Candidatus Liberibacter solanacearum) associated with zebra chip disease of the crop. In recent years, there have been no studies regarding resistance of potato to the potato psyllid or the bacterial pathogen that the psyllid transmits. Thus, the objectives of this study were to determine the effects of potato germplasm on adult potato psyllid behavior and transmission of Ca. L. psyllaurous. A total of twenty-two potato ( Solanum tuberosum L.) breeding clones and varieties were examined. Plant genotype significantly affected the occurrence and duration of psyllid probing, the duration of psyllid cleaning, resting and the amount of time psyllids spent off the potato leaflet as well as transmission of Ca. L. psyllaurous. For the potato genotypes in which there were significant decreases in transmission compared to controls, there was often an unclear relationship between the occurrences and duration of behaviors and subsequent bacterial transmission. We discuss the implications of our results for an integrated pest management program for the potato psyllid and Ca. L. psyllaurous control on potatoes.

Identification of a β-glucosidase hydrolyzing tuberonic acid glucoside in rice ( Oryza sativa L.)

Tuberonic acid (TA) and its glucoside (TAG) have been isolated from potato ( Solanum tuberosum L.) leaflets and shown to exhibit tuber-inducing properties. These compounds were reported to be biosynthesized from jasmonic acid (JA) by hydroxylation and subsequent glycosylation, and to be contained in various plant species. Here we describe the in vivo hydrolytic activity of TAG in rice. In this study, the TA resulting from TAG was not converted into JA. Tuberonic acid glucoside (TAG)-hydrolyzing β-glucosidase, designated OsTAGG1, was purified from rice by six purification steps with an ∼4300-fold purification. The purified enzyme migrated as a single band on native PAGE, but as two bands with molecular masses of 42 and 26 kDa on SDS–PAGE. Results from N-terminal sequencing and peptide mass fingerprinting of both polypeptides suggested that both bands were derived from a single polypeptide, which is a member of the glycosyl hydrolase family 1. In the native enzyme, the K m and V max values of TAG were 31.7 μM and 0.25 μkatal/mg protein, OsTAGG1 preferentially hydrolyzed TAG and methyl TAG. Here we report that OsTAGG1 is a specific β-glucosidase hydrolyzing TAG, which releases the physiologically active TA.