Provided are plants that express, or overexpress, a pPLAIII.delta. protein. Constitutive or seed-specific expression of pPLAIII.delta. protein in Arabidopsis increases seed oil content, the amount of C20 and C22 fatty acids, and the amount of C56, C58, and C60 triacylglycerols, effectively resulting in significantly higher oil yield per plant. Use of pPLAIII.delta. is therefore an effective biotechnological tool to significantly increase plant yield, including oil, and the amount of high value long chain fatty acids in agricultural and horticultural crops, especially oilseed crops.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was made with government support under Award # DE-SC0001295 from the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences (BES), Materials Sciences and Engineering Division; MCB-0922879 from the National Science Foundation; and 30900787 from the National Natural Science Foundation of China. Instrument acquisition and method development at the Kansas Lipidomics Research Center was supported by grants MCB-0920663, DBI-0521587 from the National Science Foundation, and a Kansas Experimental Program to Stimulate Competitive Research Award EPS-0236913 subaward. The U.S. government has certain rights in the invention.