Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolla non-organogenic callus with loosely attached constituent cells
Absence of arabinan in the side chains of the pectic polysaccharides strongly associated with cell walls of Nicotiana plumbaginifolla non-organogenic callus with loosely attached constituent cells
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DOI：
10.1007/s004250100559
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发表时间：
2001-10-01
期刊：
影响因子：
4.3
通讯作者：
Satoh, S
中科院分区：
文献类型：
--
作者：
Iwai, H;Ishii, T;Satoh, S
当烟叶单倍体植株的叶片。用T-DNA转化并在诱导芽培养基上培养后，约7%的叶片上出现了非器官性愈伤组织，称为nolac（指细胞附着松散的非器官性愈伤组织）。相比之下，正常愈伤组织是在二倍体植物的t - dna转化的叶片上产生的，而在单倍体和二倍体植物的未转化的叶片上产生。透射电镜显示，突变体愈伤组织（nolac-H14）的中间片层和细胞壁几乎没有被钌红染色，而正常愈伤组织的整个细胞壁和中间片层都被钌红染色。在nolac-H14愈伤组织培养中，与正常愈伤组织培养相比，半纤维素部分中果胶多糖的糖组分水平降低，培养基中果胶多糖的糖组分水平升高。这些结果表明，果胶多糖在nolac-H14愈伤组织的细胞壁和中间薄片中没有保留。在nolac-H14中，从所有细胞壁部分和培养基中纯化的果胶多糖中，阿拉伯糖与半乳糖的比例很低，特别是在半纤维素部分。nolac-H14半纤维素部分的果胶多糖中存在低水平的阿拉伯糖糠基(T-Ara(f)、5-Ara(f)、2,5- ara （f)和3,5- ara (f)）残基，表明nolac-H14中不存在主要由线性阿拉伯糖组成的中性糖侧链。富含阿拉伯糖的果胶与纤维素-半纤维素复合物密切相关，可能在细胞壁结构的细胞间附着中起重要作用。
When leaf disks from haploid plants of Nicotiana plumbaginifolia Viv. were transformed with T-DNA and cultured on shoot-inducing medium, non-organogenic callus, designated nolac (for non-organogenic callus with loosely attached cells), appeared on approximately 7% of leaf disks. In contrast, normal callus was generated on T-DNA-transformed leaf disks from diploid plants and on non-transformed leaf disks from haploid and diploid plants. Transmission electron microscopy revealed that the middle lamellae and the cell walls of one line of mutant callus (nolac-H14) were barely stained by ruthenium red, even after demethylesterification with NaOH, whereas the entire cell wall and the middle lamella were strongly stained in normal callus. In cultures of nolac-H14 callus, the level of sugar components of pectic polysaccharides in the hemicellulose fraction was reduced and that in the culture medium was elevated, as compared with cultures of normal callus. These results indicate that pectic polysaccharides are not retained in the cell walls and middle lamellae of nolac-H14 callus. In nolac-H14, the ratio of arabinose to galactose was low in the pectic polysaccharides purified from all cell wall fractions and from the medium, in particular, in the hemicellulose fractions. The low levels of arabinofuranosyl (T-Ara(f), 5-Ara(f), 2,5-Ara(f) and 3,5-Ara(f)) residues in the pectic polysaccharides of the hemicellulosic fraction of nolac-H14 indicated that no neutral-sugar side chains, composed mainly of linear arabinan, were present in nolac-H14. Arabinose-rich pectins, which are strongly associated with cellulose-hemicellulose complexes, might play an important role in intercellular attachment in the architecture of the cell wall.