Pollen-free plants can be produced by targeting two bacterial genes into the houseplant Pelargonium, new research suggests.
The paper, published in the BioMed Central journal, BMC Plant Biology describes the work of researchers from the Instituto de Biologia Molecular e Celular de Plantas (IBMCP) and BIOMIVA S.L in Spain. The team used genetic engineering techniques to incorporate new DNA into the houseplant.
The researchers modified Agrobacterium tumefaciens – the bacteria responsible for causing crown gall disease – to carry two altered genes. The first gene encoded the enzyme isopentenyl phosphotransferase (ipt), designed to increase the amount of cytokinin, a plant hormone that prevents senescence. The second gene was engineered to selectively destroy pollen-producing anthers.
The modified DNA was injected by the bacteria into Pelargonium zonale cells, subsequently integrating it into the plant’s genome. The researchers then grew individual plants from the transgenic cells.
The resulting plants carrying the modified genes were more compact, and possessed more branches and leaves than normal. Additionally, the plants had smaller leaves, flowers with more vibrant colours, and lived longer than usual due to the extra cytokinin.
Dr Luis Cañas, One of the researchers from IBMCP explained: “The ipt enzyme catalyses the rate-limiting step for cytokine biosynthesis in plants and consequently extra ipt, provided transgenically, produces more cytokinin and prevents the plant cells from ageing. In addition, the use of anther-specific promoter from pea driving the expression of a bacterial gene (ribonuclease), prevents the development of male progenitor cells into anthers and pollen, resulting in pollen-free flowers.”
Generating long-life plants with increased cytokinin is good news for gardeners keen to display their flowers for as long as possible. The lack of pollen makes these plants ideal for hay fever suffers and also prevents the risk of the transgene contaminating other plants in the environment. However, lazy gardeners beware… the transgene plants will still need to be watered regularly.