Studies on the mechanism of auxin-induced elongation growth in Poaceae plants

我们纯化并鉴定了5种与大麦细胞壁结合的葡聚糖酶：[1]，内切-1，3; 1，4-葡聚糖酶（31 KD）; [2]，内切-1，3-葡聚糖酶-1（31 kD）; [3]，内切-1，3-葡聚糖酶-2（31 kD）; [4]，外切葡聚糖酶-1（66 kD）; [5]，外切葡聚糖酶-2（68 kD）。禾谷类植物中参与1，3; 1，4-葡聚糖降解的酶可能是葡聚糖酶[1]和[4]。外切葡聚糖酶-1 [4]对1，3; 1，4-β-葡聚糖具有最高活性，并且占与细胞壁结合的总葡聚糖酶活性的60%。内切葡聚糖酶[1]引起1，3; 1，4-β-葡聚糖的剧烈分子下移。测定了葡聚糖酶[1]和[4]的N-末端氨基酸序列。葡聚糖酶[4]的序列（30个AA残基）与水稻基因组DNA的cDNA序列（D40610）具有高度的同源性。葡聚糖酶[1]的序列（5个AA残基）与水稻cDNA表达标签（D39445）同源。测定了D39445 cDNA的3'端和5'端各400 bp的核苷酸序列。这些结果为进一步研究生长素对禾谷类植物伸长生长中葡聚糖酶基因上游顺式元件的调控机制奠定了基础。

We purified and identified five glucanases bound to barley cell walls ; [1], endo-1,3 ; 1,4-glucanase (31KD) ; [2], endo-1,3-glucanase-1 (31kD) ; [3], endo-1,3-glucanase-2 (31kD) ; [4], exo-glucanase-1 (66kD) ; [5], exo-glucanase-2 (68kD). The enzymes involved in 1,3 ; 1,4-glucan degradation in cereal plants are likely glucanase [1] and [4]. The exo-glucanase-1 [4] has the highest activity toward 1,3 ; 1,4-beta-glucans, and accounts for the 60% of total glucanase activity bound to the cell walls. The endo-glucanase [1] caused a drastic molecular downshift of 1,3 ; 1,4-beta-glucans. N-terminal amino acid sequences of glucanase [1] and [4] were determined. The sequence of glucanase [4] (30 AA residues) has a high homology to cDNA sequence of genomic DNA of rice (D40610). The sequence of glucanase [1] (five AA residues) is homorogous to cDNA expression tag of rice (D39445). The mucleotide sequence if 400 bp from 3' and 5' end of the D39445 cDNA were determined. These results serves as the basic knowledge for the future study on the regulation mechanism of auxin on cis element of the upstream of glucanase genes in elongation growth of cereal plants.