国家自然科学基金No.41271487;公益性行业农业科研专项No.201303106;国家重点基础性科技专项No.2013FY111100 Supported by the National Natural Science Foundation of ChinaNo.41271487,the Special Fund for Agro-scientific Research in the Public Interest of ChinaNo.201303106 and the Special Fund for basic science and technology of ChinaNo.2013FY111100