Tuesday, January 14, 2014

Yeda's US Patent No. 8,629,259 directed to tailor-made thermotolerance for photosynthetic organisms

In US Patent No. 8,629,259 (issued January 14, 2014), Yeda Research and Development Co. Ltd. notes

Numerous studies showed that the photosynthetic energy conversion by PSII RC is highly sensitive to irradiation and temperature variations [Takahashi et al., Plant Cell Physiol 45, 251-5 (2004); Murata et al Biochim Biophys Acta 1767, 414-21 (2007)]. Also, recent studies have suggested that the PSII RC is a key player in regulating the rate of photosynthetic energy conversion in response to the prevailing temperature [Yamasaki et al., Plant Physiol 128, 1087-97 (2002)].

Taking into consideration the global warming effect, annual and even daily changes in temperature in aquatic areas (e.g., oceans, small lakes and ponds), dramatically narrow the efficiency of biomass production of thermophilic and mesophilic microalgal strains as well as of different strains of cyanobacteria and thus limits their growth to the tropical arena. Even there, current global heating is expected to exceed the thermotolerance and production efficacy of these organisms [Wraight, Front Biosci 9, 309-37 (2004); Behrenfeld et al. Nature 444, 752-5 (2006)]. Although the expected changes in global temperatures are only in the order of several degrees, it is predicted that biomass production may be dramatically effected.

The increased need for biofuel and the concomitant shortage of food across the world underscores the urgent need for methods of increasing resistance of plants, algea and microalgae to ambient temperature changes.

Claims of US '259 include:

Claim 1. An isolated polynucleotide comprising the nucleic acid sequence encoding a D1 polypeptide as set forth in SEQ ID NO: 36 of a Type II reaction center of a photosynthetic organism, wherein said D1 polypeptide comprises amino acid sequence modifications at a D1/D2 interface position corresponding to Serine 209 of SEQ ID NO: 36 and a position corresponding to Serine 212 of SEQ ID NO: 36, said amino acid modifications impart said type II reaction center with an activity under a higher temperature range than that of a type II reaction center endogenous to said photosynthetic organism.

Claim 7. A method of increasing activity of a type II reaction center of a photosynthetic organism under non-physiological temperature, the method comprising introducing into the photosynthetic organism the isolated polynucleotide of claim 1, thereby increasing the activity of a type II reaction center under a non-physiological temperature.


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