Always mention in your resume and cover letter that you are willing to learn, grasp things quickly and can adapt to different conditions and situations easily. This will strengthen your resume and even if you are under-qualified for the job, the recruiter will get an idea that you can be trained according to their requirements. Also, if you are already pursuing or enrolled yourself for a diploma course or certification for the job requirements, mention that in the resume and also provide instances in your cover letter where you have learnt a new skill quickly in the past.
You might be hired in the company as unpaid or less paid as they plan to try you and test your capabilities. Prepare yourself for such scenarios and offer time period till when you can manage with the pay amount while simultaneously proving yourself to the company. You can also take up an assignment or project to showcase your skills to the recruiter, that will also convince them to hire you if you do good at the project.
Your enthusiasm to work with the company, your confidence levels and willingness to learn are qualities that come far above the listed qualifications of a company so go and apply for the job you have recently spot in an ad while working on getting the additional qualifications!
All the Best!
