Tuesday, January 25, 2011

Metabolites Studies in Dragon Fruits (Abstract).

YS Sew1, J Baharom 1, M Yaakob 2 and Z Meon 2

1Biotechnology Research Centre, 2Station Management Centre,
Malaysian Agricultural Research and Development Research Institute
MARDI Headquarters, 43400 Serdang, Selangor D.E., Malaysia
Correspondence: sewyshin@mardi.gov.my


Pitayas had gained much interest in society because of its exotic features, attractive colour, nutritional value and pleasant taste. Phenolic compounds and high phytoalbumin antioxidants value of pitayas are believed to prevent the formation of cancer-causing free radicals. However, research on the molecular studies of pitayas is very lacking and gene information of pitayas particularly in regards to their health benefit phyto-chemicals deposited in the public databases is extremely limited. With the aim to enrich genes information and identify genes that associated with secondary metabolism of red pitaya, we have carried out transcriptome study on a local variety of red pitaya (Hylocereus polyrhizus).


Red pitayas were collected from MARDI Kundang Station with different ripening index. Total RNA of red pitaya fruits with 35 days after anthesis (DAA) were extracted and purified to get high quality total RNA. The purified total RNA was then subjected to Solexa sequencing using paired-end mRNA-seq method. The mRNA-seq sequencing results showed that total number of red pitaya paired-end reads obtained was 18,530,028 sequences and total number nucleotides obtained was 1,389,752,100nt. Sequence assembly using Velvet software revealed a total of 106,867 nodes. After the sequence filtering process (set value as >80bp/node), we obtained 62,333 nodes. The homology search on the filtered sequences against non-redundant nucleic acid database (NR) showed that 31,423 nodes with significant E-value≤10-5. It was found that there were at least 97 nodes mapped to secondary metabolic pathways via Blast2Go analysis, particularly the biosynthesis pathways of phenylproparoid, betalain, flavonoid, carotenoid and monoterpenoid.


The identification of genes involved in secondary metabolism and their corresponding biochemical pathways will enable us in harnessing the potential of red pitaya as functional food with optimal level of beneficial phyto-chemicals and also to control the production of those phyto-nutrients through genetic manipulation.

Dragon Fruit Farm In Bukit Mertajam

A visit was made to observe the conditions of two dragon farms in Bukit Mertajam, Penang - red and white varieties. Suprisingly, that both farms were in good conditions meaning that they free from diseases. The yield was about 1.1 ton per ac. per month which is very high. Ex-farm price was good which is about RM5.00 per kg.  Some of the pictures of the farm as below;

The farmer showing his farm and explained some ideas pertaining dragon fruit growing.

 Some of the chemicals using to control pests. Newly blended.
Agarwood trees intercropped with dragon fruits (3 years old) -can not be seen  from far.
Agarwood (gaharu) seedlings ready to be planted .

From my observations, I may conclude that.

1. The sanitation and crop husbandary  was good where diseases and pests surveillance were carried daily.
2. Trained workers is very necessary  where quick action is taken whenever needed.
3. Good input particularly fertilizer quality.
4. Good spraying techniques using boom sprayers to cover most of plant parts.
5. Only reserved visitors allowed. Not opened to all as to control disease and pests .

The farmers was very happy with the farms as he has won twice in the farm competition that was held recently.  I may summarize that the farm could produce quality planting materials as long it follows SIRIM standard.

It is good to know that this farmer also planted agarwood (gaharu) intercropped with dragon fruits. This is done as to increase farm income in the future. Matured agarwood  will fetched up to RM40,000 (fourty thousand)  per kg once marketable after seven years to make perfumes.
Should anyone interested to know more about this farm please kindly email me zainudinhaji@gmail.com.
We are happy to help you in whatever way we can.