Cucurbits, pepper, eggplant, legumes and other vegetables

This section is related to the biotechnology of a number of vegetables that are botanically and morphologically unrelated but that have been associated because they are generally secondary crops on the world scale as compared to the species dealt with in the previous sections. However, some of them may have great importance in some areas as they provide an essential part of the diet and/or an important income complement for farmers.

The group includes:

• fleshy fruits of the cucurbitaceae (melon, squash, cucumber) and solaneaceae (pepper, eggplant) families that are eaten raw or after cooking
• legumes other than soybean that are eaten as vegetables such as peas and beans
• bulky organs other than potato corresponding to roots (carrots), tubers (sweet potatoes) and bulbs (Allium species such as onion and garlic)
• leafy vegetables including lettuce, spinach and brassica species (cabbage, broccoli, cauliflower, etc.).

Overall these crops have received less attention in terms of genetic engineering than other major crops such as maize, rice or soybean or than model plants such as Arabidopsis and tobacco, although progress in the transformation procedures in major crops or model plants has been beneficial to secondary species. Nevertheless, some of the species covered in this review remain recalcitrant to transformation and in many cases, although successful gene transfer has been claimed, the efficiency is too low for routine transformation and/or is restricted to certain cultivars.