|XIE, WENSHUANG - Ohio Agricultural Research & Development Center|
|MORENO, ROGERIO - Embrapa|
|DA COSTA, BERNARDO - US Department Of Agriculture (USDA)|
|MATTOSO, LUIS - Embrapa|
|GONCALVES, PAULO DE SOUZA - Embrapa|
|CORNISH, KATRINA - Ohio Agricultural Research & Development Center|
Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/22/2015
Publication Date: 9/22/2015
Citation: Xie, W., Mcmahan, C.M., Moreno, R.M., Da Costa, B.M., Mattoso, L.H., Goncalves, P., Cornish, K. 2015. Studies of the latex of Brazilian IAC series clones from Hevea brasiliensis. Association for the Advancement of Industrial Crops Conference. 7:300-307.
Interpretive Summary: Natural rubber is a strategic raw material used in many industrial applications. The primary commercial source of natural rubber, a polymer of cis-1,4-polyisoprene, comes from the Brazilian rubber tree (Hevea brasiliensis). Brazil imported over 200,000 tons of natural rubber (value over $1 billion) in 2011, thus continues to develop new H. brasiliensis clones for high quality and yield rubber to meet the domestic demand (Moreno et al. 2007). The technological properties of latex and rubber of several of these clones had been evaluated (Moreno et al. 2005 and 2007). From a biochemical perspective a better understanding of the natural rubber biosynthesis and its regulation will provide valuable information for breeding high quality and high yield clones.
Technical Abstract: Natural rubber is an important commodity industrial crop that mainly derives from Hevea brasiliensis. Most natural rubber production is in Southeast Asia, but significant cultivar development takes place in Brazil, the original origin of current commercial H. brasiliensis cultivars. Thus it is critical to assess more productive new H. brasiliensis clones for high yield and quality rubber for São Paulo State, Brazil’s largest planted region. Natural rubber is synthesized by rubber transferase, a cis-prenyltransferase associated with washed rubber particles. The purpose of this study was to investigate the seasonal effects on H. brasiliensis clones with respect to rubber transferase activity, magnesium concentration, latex protein content and rubber content. Seven H. brasiliensis clones (IAC 40, IAC 56, IAC 300, IAC 301, IAC 302, IAC 303 and RRIMM600) were selected and latex was collected eight times from 2005 to 2006 to span different seasons from a plantation in São Paulo, Brazil. Latex protein and rubber content varied among different clones and seasons. Protein content reached the highest level in September during the middle of the foliation stage. Magnesium concentrations in latex determined from a single collection point also varied among different clones range from as low as 1 mM (IAC 56) to as high as 5.6 mM (IAC 302). Washed rubber particles were isolated from all collections (total 56) and rubber transferase activity of washed rubber particles showed significant variations among the different clones and seasons. Of those clones IAC 56 had highest rubber transferase activity, the control cultivar RRIM600 at middle and clone IAC 301 had the lowest activity. These findings will provide some insights together with some other important technological parameters to inform the H. brasiliensis breeding program in Brazil.