NOVELTY - An isolated polypeptide having endoglucanase activity, selected from: a polypeptide comprising an amino acid sequence comprising a partial amino acid sequence of fully defined 112 amino acids (SEQ ID NO: 2), given in the specification, or the partial amino acid sequence of fully defined 73 amino acids (SEQ ID NO: 4), given in the specification; and a partial nucleotide sequence of fully defined 509 bp (SEQ ID NO: 1), given in the specification, or the partial nucleotide sequence of fully defined 298 bp (SEQ ID NO: 3), given in the specification, is new.    USE - The isolated polypeptide having endoglucanase activity, isolated polynucleotide, recombinant host cell, and methods are useful for producing the polypeptide; for producing a mutant of a parent cell; for producing a transgenic plant, plant part or plant cell; for inhibiting the expression of a polypeptide having endoglucanase activity in the cell; for degrading or converting a cellulosic material; for producing a fermentation product; and for fermenting the cellulosic material (all claimed).    DETAILED DESCRIPTION - An isolated polypeptide having endoglucanase activity, selected from: (a) a polypeptide comprising an amino acid sequence comprising a partial amino acid sequence having at least 75% identity to the partial amino add sequence of fully defined 112 amino acids (SEQ ID NO: 2), given in the specification, or at least 85% identity to the partial amino acid sequence of fully defined 73 amino acids (SEQ ID NO: 4), given in the specification; (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence comprising a partial nucleotide sequence that hybridizes under at least high stringency conditions with (i) the partial nucleotide sequence of fully defined 509 bp (SEQ ID NO: 1), given in the specification, or the partial nucleotide sequence of fully defined 298 bp (SEQ ID NO: 3), given in the specification, (ii) the cyclic DNA (cDNA) sequence contained in the partial nucleotide sequence of SEQ ID NO: 1 or the partial nucleotide sequence of SEQ ID NO: 3, or (iii) a full-length complementary strand of (i) or (ii); (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence comprising a partial nucleotide sequence having at least 75% identity to the partial nucleotide sequence of SEQ ID NO: 1 or at least 85% identity to the partial nucleotide sequence of SEQ ID NO: 3; and (d) a variant comprising an amino acid sequence comprising a substitution, deletion, and/or insertion of several amino acids of the partial amino acid sequence of SEQ ID NO: 2 or the partial amino acid sequence of SEQ ID NO: 4, is new. INDEPENDENT CLAIMS are:    (1) an isolated polynucleotide comprising the nucleotide sequence that encodes the polypeptide;    (2) a nucleic acid construct comprising the polynucleotide operably linked to one or more control sequences that direct the production of the polypeptide in an expression host;    (3) a recombinant host cell comprising the nucleic acid construct;    (4) a method of producing the polypeptide, comprising: (a) cultivating a cell, which in its wild-type form produces the polypeptide, under conditions conducive for production of the polypeptide; and (b) recovering the polypeptide;    (5) a method of producing a mutant of a parent cell, comprising disrupting or deleting the nucleotide sequence encoding the polypeptide, which results in the mutant producing less of the polypeptide than the parent cell;    (6) a transgenic plant, plant part or plant cell transformed with the polynucleotide encoding the polypeptide;    (7) a double-stranded inhibitory RNA (dsRNA) molecule comprising a subsequence of the polynucleotide, where optionally the dsRNA is a small interfering RNA (siRNA) or a micro RNA (miRNA) molecule;    (8) a method of inhibiting the expression of a polypeptide having endoglucanase activity in the cell, comprising administering to the cell or expressing in the cell the dsRNA molecule, where the dsRNA comprises the subsequence of the polynucleotide;    (9) a method for degrading or converting a cellulosic material, comprising: treating the cellulosic material with a cellulolytic enzyme composition in the presence of the polypeptide having endoglucanase activity, where the presence of the polypeptide having endoglucanase activity increases the degradation of cellulosic material compared to the absence of the polypeptide having endoglucanase activity;    (10) a method for producing a fermentation product, comprising: (a) saccharifying the cellulosic material with the cellulolytic enzyme composition in the presence of the polypeptide having endoglucanase activity, where the presence of the polypeptide having endoglucanase activity increases the degradation of cellulosic material compared to the absence of the polypeptide having endoglucanase activity; (b) fermenting the saccharified cellulosic material of (a) with one or more fermenting microorganisms to produce the fermentation product; and (c) recovering the fermentation product from the fermentation; and    (11) a method of fermenting the cellulosic material, comprising: fermenting the cellulosic material with one or more fermenting microorganisms, where the cellulosic material is saccharified with the cellulolytic enzyme composition in the presence of the polypeptide having endoglucanase activity and the presence of the polypeptide having endoglucanase activity increases the degradation of the cellulosic material compared to the absence of the polypeptide having endoglucanase activity.