Department of Plant and Microbial Biology, UC Berkeley and Physical Biosciences Division, LBNL, Berkeley, CA 94720, USA. dzhi@compbio.berkeley.edu|Department of Plant and Microbial Biology, UC Berkeley and Physical Biosciences Division, LBNL, Berkeley, CA 94720, USA. dzhi@compbio.berkeley.edu|Department of Plant and Microbial Biology, UC Berkeley and Physical Biosciences Division, LBNL, Berkeley, CA 94720, USA. dzhi@compbio.berkeley.edu