Romaine lettuce latex deters feeding of banded cucumber beetle: a vehicle for deployment of biochemical defenses

Abstract

Latex is widely found among plant species and is known to play a defensive role against certain herbivores. Two romaine lettuce, Lactuca sativa L. (Asteraceae) cultivars, ‘Valmaine’ (resistant) and ‘Tall Guzmaine’ (susceptible), were selected to study the potential of latex as a defense mechanism against the banded cucumber beetle, Diabrotica balteata LeConte (Coleoptera: Chrysomelidae). Latex from Valmaine strongly inhibited feeding of adult D. balteata compared to latex from Tall Guzmaine when applied to the surface of artificial diet. Beetles consumed significantly less diet from disks treated with Valmaine latex than they consumed from diet treated with Tall Guzmaine latex, in both choice and no‐choice tests. In a choice test involving diet disks treated with Valmaine latex from young leaves vs. disks treated with latex from mature leaves, the beetles consumed significantly less diet treated with latex from young leaves. No significant difference in diet consumption was found between diets treated with latex from young and mature leaves of Tall Guzmaine in choice tests. Three solvents of differing polarity (water, methanol, and methylene chloride) were tested to extract deterrent compounds from latex; Valmaine latex extracted with water:methanol (20:80) strongly inhibited beetle feeding when applied to the surface of artificial diet. In no‐choice tests, fewer beetles were observed feeding on diet treated with water:methanol (20:80) extract of Valmaine latex than on diet treated with a similar extract of Tall Guzmaine latex, resulting in significantly less consumption of the diet treated with the Valmaine latex extract. These studies suggest that moderately polar chemicals within latex may account for resistance in Valmaine to D. balteata.

Small rubber particle proteins from Taraxacum brevicorniculatum promote stress tolerance and influence the size and distribution of lipid droplets and artificial poly(cis‐1,4‐isoprene) bodies

“…The latex of lettuce ( Lactuca sativa ), of the common dandelion ( T . officinale ) and of many other plant species contains further defence‐associated secondary metabolites and proteins (Sethi et al ., ; Konno, ; Huber et al ., ) suggesting that TbSRPPs may participate in natural rubber and/or latex defence machinery. Summarizing the knowledge gained about SRPP localization, regulation and function from previous reports (Hillebrand et al ., ; Fricke et al ., ), we hypothesized that TbSRPP1 could be the first isoform to respond to stress, followed by TbSRPP3, whereas TbSRPP4 and TbSRPP5 are mainly responsible for rubber particle integrity.…”

Cordeauxia edulis and Rhododendron tomentosum extracts disturb orientation and feeding behavior of Hylobius abietis and Phyllodecta laticollis

“…The use of plantbased compounds is one of the alternatives to control insect pests. Many studies have been conducted on the repellent and antifeedant properties of plant extracts against insect pests (e.g., Erler et al, 2006;Tapia et al, 2007;Gahukar, 2008;Sethi et al, 2008;Napal et al, 2009). Many studies have been conducted on the repellent and antifeedant properties of plant extracts against insect pests (e.g., Erler et al, 2006;Tapia et al, 2007;Gahukar, 2008;Sethi et al, 2008;Napal et al, 2009).…”

“…Through their repellent and antifeedant effects, they can manipulate insect behavior and protect host plants from phytophagous insect pests (Isman, 2008). Many studies have been conducted on the repellent and antifeedant properties of plant extracts against insect pests (e.g., Erler et al, 2006;Tapia et al, 2007;Gahukar, 2008;Sethi et al, 2008;Napal et al, 2009). However, considering the vast array of plant resources, more studies need to be undertaken to come up with effective plant-based insecticides to control phytophagous insect pests.…”

Responses of Lettuce Cultivars to Insect Pests in Southern Florida

“…Host plant resistance in lettuce to BCB and SL has been identified, as Nuessly and Nagata (1994) reported that 'Valmaine', a romaine lettuce cultivar, had a high level of resistance to SL. This cultivar was later found to be resistant to BCB (Huang et al, 2002;Sethi et al, 2008) and two lepidopterans, Trichoplusia ni and Spodoptera exigua (Sethi et al, 2006). 'Valmaine' is an obsolete cultivar that was used in lettuce production in 1970s and then used as a parent for crosses for development of romaine cultivars in the University of Florida (UF) lettuce breeding program (Guzman, 1986;Guzman and Zitter, 1983).…”