An ordered EST catalogue and gene expression profiles of cassava (Manihot esculenta) at key growth stages.
A cDNA library was constructed from the root tissues of cassava variety Huanan 124 at the root bulking stage. A total of 9,600 cDNA clones from the library were sequenced with single-pass from the 5'-terminus to establish a catalogue of expressed sequence tags (ESTs). Assembly of the resulting EST sequences resulted in 2,878 putative unigenes. Blastn analysis showed that 62.6% of the unigenes matched with known cassava ESTs and the rest had no 'hits' against the cassava database in the integrative PlantGDB database. Blastx analysis showed that 1,715 (59.59%) of the unigenes matched with one or more GenBank protein entries and 1,163 (40.41%) had no 'hits'. A cDNA microarray with 2,878 unigenes was developed and used to analyze gene expression profiling of Huanan 124 at key growth stages including seedling, formation of root system, root bulking, and starch maturity. Array data analysis revealed that (1) the higher ratio of up-regulated ribosome-related genes was accompanied by a high ratio of up-regulated ubiquitin, proteasome-related and protease genes in cassava roots; (2) starch formation and degradation simultaneously occur at the early stages of root development but starch degradation is declined partially due to decrease in UDP-glucose dehydrogenase activity with root maturity; (3) starch may also be synthesized in situ in roots; (4) starch synthesis, translocation, and accumulation are also associated probably with signaling pathways that parallel Wnt, LAM, TCS and ErbB signaling pathways in animals; (5) constitutive expression of stress-responsive genes may be due to the adaptation of cassava to harsh environments during long-term evolution.
Guangxi Key Laboratory of Subtropical Bioresource Conservation and Utilization, College of Life Science and Technology, Guangxi University, 530004, Nanning, Guangxi, People's Republic of China.
You-Zhi
YZ
Li
Ying-Hua
YH
Pan
Chang-Bin
CB
Sun
Hai-Tao
HT
Dong
Xing-Lu
XL
Luo
Zhi-Qiang
ZQ
Wang
Ji-Liang
JL
Tang
Baoshan
B
Chen
D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D015723:Gene Library; D002365:Manihot / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development; D015398:Signal Transduction; D013213:Starch / Q000096:biosynthesis / Q000235:genetics
D013213:Starch