An isolated, synthetic or recombinant nucleic acid (polynucleotide) comprising or consisting of a nucleic acid sequence: (a) encoding a polypeptide having a phosphatidylinositol-specific phospholipase C (PI-PLC) enzyme activity, and (i) having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:5 and encoding a polypeptide having at least one or more, or all, of the amino acid changes (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291 N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; (ii) encoding a polypeptide have an amino acid sequence as set forth in SEQ ID NO:6 and having at least one of the amino acid changes or substitutions (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; or (iii) a nucleic acid comprising or consisting of the sequence SEQ ID NO:7, SEQ ID NO:9 or SEQ ID NO:10; or (b) the nucleic acid sequence of (a) encoding a polypeptide having the PI-PLC enzyme activity but lacking a native signal sequence or proprotein amino acid sequence; (c) the nucleic acid sequence of (a) or (b) encoding a polypeptide having the PI-PLC enzyme activity but lacking a native promoter sequence; (d) the nucleic acid of (c) further comprising a heterologous promoter sequence or other transcriptional regulatory sequence; (e) the nucleic acid sequence of any of (a) to (d) further comprising nucleic acid encoding a heterologous amino acid sequence, or further comprising a heterologous nucleotide sequence; (f) the nucleic acid of (e), wherein the nucleic acid encoding the heterologous amino acid sequence comprises, or consists of, a sequence encoding a heterologous (leader) signal sequence, or a tag or an epitope, or the heterologous nucleotide sequence comprises a heterologous promoter sequence; (g) a nucleic acid sequence completely complementary to the nucleotide sequence of any of (a) to (f). (a) encoding a polypeptide having a phosphatidylinositol-specific phospholipase C (PI-PLC) enzyme activity, and (i) having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:5 and encoding a polypeptide having at least one or more, or all, of the amino acid changes (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291 N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; (ii) encoding a polypeptide have an amino acid sequence as set forth in SEQ ID NO:6 and having at least one of the amino acid changes or substitutions (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; or (iii) a nucleic acid comprising or consisting of the sequence SEQ ID NO:7, SEQ ID NO:9 or SEQ ID NO:10; or (i) having at least 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% sequence identity to SEQ ID NO:5 and encoding a polypeptide having at least one or more, or all, of the amino acid changes (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291 N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; (ii) encoding a polypeptide have an amino acid sequence as set forth in SEQ ID NO:6 and having at least one of the amino acid changes or substitutions (mutations) consisting of N176F, Q191G, Y205L, N244T, Y252R, M261I, Y276F, S282H, and R291N, or any combination thereof, wherein the numbering of the amino acid changes begins with amino acid 31 of SEQ ID NO: 6; or (iii) a nucleic acid comprising or consisting of the sequence SEQ ID NO:7, SEQ ID NO:9 or SEQ ID NO:10; or (b) the nucleic acid sequence of (a) encoding a polypeptide having the PI-PLC enzyme activity but lacking a native signal sequence or proprotein amino acid sequence; (c) the nucleic acid sequence of (a) or (b) encoding a polypeptide having the PI-PLC enzyme activity but lacking a native promoter sequence; (d) the nucleic acid of (c) further comprising a heterologous promoter sequence or other transcriptional regulatory sequence; (e) the nucleic acid sequence of any of (a) to (d) further comprising nucleic acid encoding a heterologous amino acid sequence, or further comprising a heterologous nucleotide sequence; (f) the nucleic acid of (e), wherein the nucleic acid encoding the heterologous amino acid sequence comprises, or consists of, a sequence encoding a heterologous (leader) signal sequence, or a tag or an epitope, or the heterologous nucleotide sequence comprises a heterologous promoter sequence; (g) a nucleic acid sequence completely complementary to the nucleotide sequence of any of (a) to (f).